#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_dbg.h>
#include <scsi/scsi_device.h>
+#include <scsi/scsi_driver.h>
#include <scsi/scsi_eh.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_tcq.h>
#define MIN_RESET_PERIOD (15*HZ)
/*
- * Macro to determine the size of SCSI command. This macro takes vendor
- * unique commands into account. SCSI commands in groups 6 and 7 are
- * vendor unique and we will depend upon the command length being
- * supplied correctly in cmd_len.
- */
-#define CDB_SIZE(cmd) (((((cmd)->cmnd[0] >> 5) & 7) < 6) ? \
- COMMAND_SIZE((cmd)->cmnd[0]) : (cmd)->cmd_len)
-
-/*
* Note - the initial logging level can be set here to log events at boot time.
* After the system is up, you may enable logging via the /proc interface.
*/
"Automation/Drive ",
};
+/**
+ * scsi_device_type - Return 17 char string indicating device type.
+ * @type: type number to look up
+ */
+
const char * scsi_device_type(unsigned type)
{
if (type == 0x1e)
EXPORT_SYMBOL(scsi_device_type);
struct scsi_host_cmd_pool {
- struct kmem_cache *slab;
- unsigned int users;
- char *name;
- unsigned int slab_flags;
- gfp_t gfp_mask;
+ struct kmem_cache *cmd_slab;
+ struct kmem_cache *sense_slab;
+ unsigned int users;
+ char *cmd_name;
+ char *sense_name;
+ unsigned int slab_flags;
+ gfp_t gfp_mask;
};
static struct scsi_host_cmd_pool scsi_cmd_pool = {
- .name = "scsi_cmd_cache",
+ .cmd_name = "scsi_cmd_cache",
+ .sense_name = "scsi_sense_cache",
.slab_flags = SLAB_HWCACHE_ALIGN,
};
static struct scsi_host_cmd_pool scsi_cmd_dma_pool = {
- .name = "scsi_cmd_cache(DMA)",
+ .cmd_name = "scsi_cmd_cache(DMA)",
+ .sense_name = "scsi_sense_cache(DMA)",
.slab_flags = SLAB_HWCACHE_ALIGN|SLAB_CACHE_DMA,
.gfp_mask = __GFP_DMA,
};
static DEFINE_MUTEX(host_cmd_pool_mutex);
+/**
+ * scsi_pool_alloc_command - internal function to get a fully allocated command
+ * @pool: slab pool to allocate the command from
+ * @gfp_mask: mask for the allocation
+ *
+ * Returns a fully allocated command (with the allied sense buffer) or
+ * NULL on failure
+ */
+static struct scsi_cmnd *
+scsi_pool_alloc_command(struct scsi_host_cmd_pool *pool, gfp_t gfp_mask)
+{
+ struct scsi_cmnd *cmd;
+
+ cmd = kmem_cache_alloc(pool->cmd_slab, gfp_mask | pool->gfp_mask);
+ if (!cmd)
+ return NULL;
+
+ memset(cmd, 0, sizeof(*cmd));
+
+ cmd->sense_buffer = kmem_cache_alloc(pool->sense_slab,
+ gfp_mask | pool->gfp_mask);
+ if (!cmd->sense_buffer) {
+ kmem_cache_free(pool->cmd_slab, cmd);
+ return NULL;
+ }
+
+ return cmd;
+}
+
+/**
+ * scsi_pool_free_command - internal function to release a command
+ * @pool: slab pool to allocate the command from
+ * @cmd: command to release
+ *
+ * the command must previously have been allocated by
+ * scsi_pool_alloc_command.
+ */
+static void
+scsi_pool_free_command(struct scsi_host_cmd_pool *pool,
+ struct scsi_cmnd *cmd)
+{
+ if (cmd->prot_sdb)
+ kmem_cache_free(scsi_sdb_cache, cmd->prot_sdb);
+
+ kmem_cache_free(pool->sense_slab, cmd->sense_buffer);
+ kmem_cache_free(pool->cmd_slab, cmd);
+}
+
+/**
+ * scsi_host_alloc_command - internal function to allocate command
+ * @shost: SCSI host whose pool to allocate from
+ * @gfp_mask: mask for the allocation
+ *
+ * Returns a fully allocated command with sense buffer and protection
+ * data buffer (where applicable) or NULL on failure
+ */
+static struct scsi_cmnd *
+scsi_host_alloc_command(struct Scsi_Host *shost, gfp_t gfp_mask)
+{
+ struct scsi_cmnd *cmd;
+
+ cmd = scsi_pool_alloc_command(shost->cmd_pool, gfp_mask);
+ if (!cmd)
+ return NULL;
+
+ if (scsi_host_get_prot(shost) >= SHOST_DIX_TYPE0_PROTECTION) {
+ cmd->prot_sdb = kmem_cache_zalloc(scsi_sdb_cache, gfp_mask);
+
+ if (!cmd->prot_sdb) {
+ scsi_pool_free_command(shost->cmd_pool, cmd);
+ return NULL;
+ }
+ }
+
+ return cmd;
+}
+
+/**
+ * __scsi_get_command - Allocate a struct scsi_cmnd
+ * @shost: host to transmit command
+ * @gfp_mask: allocation mask
+ *
+ * Description: allocate a struct scsi_cmd from host's slab, recycling from the
+ * host's free_list if necessary.
+ */
struct scsi_cmnd *__scsi_get_command(struct Scsi_Host *shost, gfp_t gfp_mask)
{
struct scsi_cmnd *cmd;
+ unsigned char *buf;
- cmd = kmem_cache_alloc(shost->cmd_pool->slab,
- gfp_mask | shost->cmd_pool->gfp_mask);
+ cmd = scsi_host_alloc_command(shost, gfp_mask);
if (unlikely(!cmd)) {
unsigned long flags;
list_del_init(&cmd->list);
}
spin_unlock_irqrestore(&shost->free_list_lock, flags);
+
+ if (cmd) {
+ buf = cmd->sense_buffer;
+ memset(cmd, 0, sizeof(*cmd));
+ cmd->sense_buffer = buf;
+ }
}
return cmd;
}
EXPORT_SYMBOL_GPL(__scsi_get_command);
-/*
- * Function: scsi_get_command()
- *
- * Purpose: Allocate and setup a scsi command block
- *
- * Arguments: dev - parent scsi device
- * gfp_mask- allocator flags
+/**
+ * scsi_get_command - Allocate and setup a scsi command block
+ * @dev: parent scsi device
+ * @gfp_mask: allocator flags
*
* Returns: The allocated scsi command structure.
*/
if (likely(cmd != NULL)) {
unsigned long flags;
- memset(cmd, 0, sizeof(*cmd));
cmd->device = dev;
- init_timer(&cmd->eh_timeout);
INIT_LIST_HEAD(&cmd->list);
spin_lock_irqsave(&dev->list_lock, flags);
list_add_tail(&cmd->list, &dev->cmd_list);
}
EXPORT_SYMBOL(scsi_get_command);
+/**
+ * __scsi_put_command - Free a struct scsi_cmnd
+ * @shost: dev->host
+ * @cmd: Command to free
+ * @dev: parent scsi device
+ */
void __scsi_put_command(struct Scsi_Host *shost, struct scsi_cmnd *cmd,
struct device *dev)
{
spin_unlock_irqrestore(&shost->free_list_lock, flags);
if (likely(cmd != NULL))
- kmem_cache_free(shost->cmd_pool->slab, cmd);
+ scsi_pool_free_command(shost->cmd_pool, cmd);
put_device(dev);
}
EXPORT_SYMBOL(__scsi_put_command);
-/*
- * Function: scsi_put_command()
- *
- * Purpose: Free a scsi command block
- *
- * Arguments: cmd - command block to free
+/**
+ * scsi_put_command - Free a scsi command block
+ * @cmd: command block to free
*
* Returns: Nothing.
*
}
EXPORT_SYMBOL(scsi_put_command);
-/*
- * Function: scsi_setup_command_freelist()
- *
- * Purpose: Setup the command freelist for a scsi host.
- *
- * Arguments: shost - host to allocate the freelist for.
- *
- * Returns: Nothing.
- */
-int scsi_setup_command_freelist(struct Scsi_Host *shost)
+static struct scsi_host_cmd_pool *scsi_get_host_cmd_pool(gfp_t gfp_mask)
{
- struct scsi_host_cmd_pool *pool;
- struct scsi_cmnd *cmd;
-
- spin_lock_init(&shost->free_list_lock);
- INIT_LIST_HEAD(&shost->free_list);
-
+ struct scsi_host_cmd_pool *retval = NULL, *pool;
/*
* Select a command slab for this host and create it if not
- * yet existant.
+ * yet existent.
*/
mutex_lock(&host_cmd_pool_mutex);
- pool = (shost->unchecked_isa_dma ? &scsi_cmd_dma_pool : &scsi_cmd_pool);
+ pool = (gfp_mask & __GFP_DMA) ? &scsi_cmd_dma_pool :
+ &scsi_cmd_pool;
if (!pool->users) {
- pool->slab = kmem_cache_create(pool->name,
- sizeof(struct scsi_cmnd), 0,
- pool->slab_flags, NULL);
- if (!pool->slab)
+ pool->cmd_slab = kmem_cache_create(pool->cmd_name,
+ sizeof(struct scsi_cmnd), 0,
+ pool->slab_flags, NULL);
+ if (!pool->cmd_slab)
+ goto fail;
+
+ pool->sense_slab = kmem_cache_create(pool->sense_name,
+ SCSI_SENSE_BUFFERSIZE, 0,
+ pool->slab_flags, NULL);
+ if (!pool->sense_slab) {
+ kmem_cache_destroy(pool->cmd_slab);
goto fail;
+ }
}
pool->users++;
- shost->cmd_pool = pool;
+ retval = pool;
+ fail:
mutex_unlock(&host_cmd_pool_mutex);
+ return retval;
+}
+static void scsi_put_host_cmd_pool(gfp_t gfp_mask)
+{
+ struct scsi_host_cmd_pool *pool;
+
+ mutex_lock(&host_cmd_pool_mutex);
+ pool = (gfp_mask & __GFP_DMA) ? &scsi_cmd_dma_pool :
+ &scsi_cmd_pool;
/*
- * Get one backup command for this host.
+ * This may happen if a driver has a mismatched get and put
+ * of the command pool; the driver should be implicated in
+ * the stack trace
*/
- cmd = kmem_cache_alloc(shost->cmd_pool->slab,
- GFP_KERNEL | shost->cmd_pool->gfp_mask);
- if (!cmd)
- goto fail2;
- list_add(&cmd->list, &shost->free_list);
- return 0;
+ BUG_ON(pool->users == 0);
- fail2:
- if (!--pool->users)
- kmem_cache_destroy(pool->slab);
- return -ENOMEM;
- fail:
+ if (!--pool->users) {
+ kmem_cache_destroy(pool->cmd_slab);
+ kmem_cache_destroy(pool->sense_slab);
+ }
mutex_unlock(&host_cmd_pool_mutex);
- return -ENOMEM;
+}
+/**
+ * scsi_allocate_command - get a fully allocated SCSI command
+ * @gfp_mask: allocation mask
+ *
+ * This function is for use outside of the normal host based pools.
+ * It allocates the relevant command and takes an additional reference
+ * on the pool it used. This function *must* be paired with
+ * scsi_free_command which also has the identical mask, otherwise the
+ * free pool counts will eventually go wrong and you'll trigger a bug.
+ *
+ * This function should *only* be used by drivers that need a static
+ * command allocation at start of day for internal functions.
+ */
+struct scsi_cmnd *scsi_allocate_command(gfp_t gfp_mask)
+{
+ struct scsi_host_cmd_pool *pool = scsi_get_host_cmd_pool(gfp_mask);
+
+ if (!pool)
+ return NULL;
+
+ return scsi_pool_alloc_command(pool, gfp_mask);
}
+EXPORT_SYMBOL(scsi_allocate_command);
-/*
- * Function: scsi_destroy_command_freelist()
+/**
+ * scsi_free_command - free a command allocated by scsi_allocate_command
+ * @gfp_mask: mask used in the original allocation
+ * @cmd: command to free
+ *
+ * Note: using the original allocation mask is vital because that's
+ * what determines which command pool we use to free the command. Any
+ * mismatch will cause the system to BUG eventually.
+ */
+void scsi_free_command(gfp_t gfp_mask, struct scsi_cmnd *cmd)
+{
+ struct scsi_host_cmd_pool *pool = scsi_get_host_cmd_pool(gfp_mask);
+
+ /*
+ * this could trigger if the mask to scsi_allocate_command
+ * doesn't match this mask. Otherwise we're guaranteed that this
+ * succeeds because scsi_allocate_command must have taken a reference
+ * on the pool
+ */
+ BUG_ON(!pool);
+
+ scsi_pool_free_command(pool, cmd);
+ /*
+ * scsi_put_host_cmd_pool is called twice; once to release the
+ * reference we took above, and once to release the reference
+ * originally taken by scsi_allocate_command
+ */
+ scsi_put_host_cmd_pool(gfp_mask);
+ scsi_put_host_cmd_pool(gfp_mask);
+}
+EXPORT_SYMBOL(scsi_free_command);
+
+/**
+ * scsi_setup_command_freelist - Setup the command freelist for a scsi host.
+ * @shost: host to allocate the freelist for.
*
- * Purpose: Release the command freelist for a scsi host.
+ * Description: The command freelist protects against system-wide out of memory
+ * deadlock by preallocating one SCSI command structure for each host, so the
+ * system can always write to a swap file on a device associated with that host.
*
- * Arguments: shost - host that's freelist is going to be destroyed
+ * Returns: Nothing.
+ */
+int scsi_setup_command_freelist(struct Scsi_Host *shost)
+{
+ struct scsi_cmnd *cmd;
+ const gfp_t gfp_mask = shost->unchecked_isa_dma ? GFP_DMA : GFP_KERNEL;
+
+ spin_lock_init(&shost->free_list_lock);
+ INIT_LIST_HEAD(&shost->free_list);
+
+ shost->cmd_pool = scsi_get_host_cmd_pool(gfp_mask);
+
+ if (!shost->cmd_pool)
+ return -ENOMEM;
+
+ /*
+ * Get one backup command for this host.
+ */
+ cmd = scsi_host_alloc_command(shost, gfp_mask);
+ if (!cmd) {
+ scsi_put_host_cmd_pool(gfp_mask);
+ shost->cmd_pool = NULL;
+ return -ENOMEM;
+ }
+ list_add(&cmd->list, &shost->free_list);
+ return 0;
+}
+
+/**
+ * scsi_destroy_command_freelist - Release the command freelist for a scsi host.
+ * @shost: host whose freelist is going to be destroyed
*/
void scsi_destroy_command_freelist(struct Scsi_Host *shost)
{
+ /*
+ * If cmd_pool is NULL the free list was not initialized, so
+ * do not attempt to release resources.
+ */
+ if (!shost->cmd_pool)
+ return;
+
while (!list_empty(&shost->free_list)) {
struct scsi_cmnd *cmd;
cmd = list_entry(shost->free_list.next, struct scsi_cmnd, list);
list_del_init(&cmd->list);
- kmem_cache_free(shost->cmd_pool->slab, cmd);
+ scsi_pool_free_command(shost->cmd_pool, cmd);
}
-
- mutex_lock(&host_cmd_pool_mutex);
- if (!--shost->cmd_pool->users)
- kmem_cache_destroy(shost->cmd_pool->slab);
- mutex_unlock(&host_cmd_pool_mutex);
+ shost->cmd_pool = NULL;
+ scsi_put_host_cmd_pool(shost->unchecked_isa_dma ? GFP_DMA : GFP_KERNEL);
}
#ifdef CONFIG_SCSI_LOGGING
scsi_print_command(cmd);
if (level > 3) {
printk(KERN_INFO "buffer = 0x%p, bufflen = %d,"
- " done = 0x%p, queuecommand 0x%p\n",
+ " queuecommand 0x%p\n",
scsi_sglist(cmd), scsi_bufflen(cmd),
- cmd->done,
cmd->device->host->hostt->queuecommand);
}
}
#endif
-/*
- * Assign a serial number to the request for error recovery
+/**
+ * scsi_cmd_get_serial - Assign a serial number to a command
+ * @host: the scsi host
+ * @cmd: command to assign serial number to
+ *
+ * Description: a serial number identifies a request for error recovery
* and debugging purposes. Protected by the Host_Lock of host.
*/
static inline void scsi_cmd_get_serial(struct Scsi_Host *host, struct scsi_cmnd *cmd)
cmd->serial_number = host->cmd_serial_number++;
}
-/*
- * Function: scsi_dispatch_command
- *
- * Purpose: Dispatch a command to the low-level driver.
- *
- * Arguments: cmd - command block we are dispatching.
+/**
+ * scsi_dispatch_command - Dispatch a command to the low-level driver.
+ * @cmd: command block we are dispatching.
*
- * Notes:
+ * Return: nonzero return request was rejected and device's queue needs to be
+ * plugged.
*/
int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
{
unsigned long timeout;
int rtn = 0;
+ /*
+ * We will use a queued command if possible, otherwise we will
+ * emulate the queuing and calling of completion function ourselves.
+ */
+ atomic_inc(&cmd->device->iorequest_cnt);
+
/* check if the device is still usable */
if (unlikely(cmd->device->sdev_state == SDEV_DEL)) {
/* in SDEV_DEL we error all commands. DID_NO_CONNECT
* returns an immediate error upwards, and signals
* that the device is no longer present */
cmd->result = DID_NO_CONNECT << 16;
- atomic_inc(&cmd->device->iorequest_cnt);
- __scsi_done(cmd);
+ scsi_done(cmd);
/* return 0 (because the command has been processed) */
goto out;
}
* future requests should not occur until the device
* transitions out of the suspend state.
*/
+
scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
SCSI_LOG_MLQUEUE(3, printk("queuecommand : device blocked \n"));
host->resetting = 0;
}
- /*
- * AK: unlikely race here: for some reason the timer could
- * expire before the serial number is set up below.
- */
- scsi_add_timer(cmd, cmd->timeout_per_command, scsi_times_out);
-
scsi_log_send(cmd);
/*
- * We will use a queued command if possible, otherwise we will
- * emulate the queuing and calling of completion function ourselves.
- */
- atomic_inc(&cmd->device->iorequest_cnt);
-
- /*
* Before we queue this command, check if the command
* length exceeds what the host adapter can handle.
*/
- if (CDB_SIZE(cmd) > cmd->device->host->max_cmd_len) {
+ if (cmd->cmd_len > cmd->device->host->max_cmd_len) {
SCSI_LOG_MLQUEUE(3,
- printk("queuecommand : command too long.\n"));
+ printk("queuecommand : command too long. "
+ "cdb_size=%d host->max_cmd_len=%d\n",
+ cmd->cmd_len, cmd->device->host->max_cmd_len));
cmd->result = (DID_ABORT << 16);
scsi_done(cmd);
}
spin_lock_irqsave(host->host_lock, flags);
+ /*
+ * AK: unlikely race here: for some reason the timer could
+ * expire before the serial number is set up below.
+ *
+ * TODO: kill serial or move to blk layer
+ */
scsi_cmd_get_serial(host, cmd);
if (unlikely(host->shost_state == SHOST_DEL)) {
}
spin_unlock_irqrestore(host->host_lock, flags);
if (rtn) {
- if (scsi_delete_timer(cmd)) {
- atomic_inc(&cmd->device->iodone_cnt);
- scsi_queue_insert(cmd,
- (rtn == SCSI_MLQUEUE_DEVICE_BUSY) ?
- rtn : SCSI_MLQUEUE_HOST_BUSY);
- }
+ scsi_queue_insert(cmd, (rtn == SCSI_MLQUEUE_DEVICE_BUSY) ?
+ rtn : SCSI_MLQUEUE_HOST_BUSY);
SCSI_LOG_MLQUEUE(3,
printk("queuecommand : request rejected\n"));
}
}
/**
- * scsi_req_abort_cmd -- Request command recovery for the specified command
- * cmd: pointer to the SCSI command of interest
- *
- * This function requests that SCSI Core start recovery for the
- * command by deleting the timer and adding the command to the eh
- * queue. It can be called by either LLDDs or SCSI Core. LLDDs who
- * implement their own error recovery MAY ignore the timeout event if
- * they generated scsi_req_abort_cmd.
- */
-void scsi_req_abort_cmd(struct scsi_cmnd *cmd)
-{
- if (!scsi_delete_timer(cmd))
- return;
- scsi_times_out(cmd);
-}
-EXPORT_SYMBOL(scsi_req_abort_cmd);
-
-/**
* scsi_done - Enqueue the finished SCSI command into the done queue.
* @cmd: The SCSI Command for which a low-level device driver (LLDD) gives
* ownership back to SCSI Core -- i.e. the LLDD has finished with it.
*
- * This function is the mid-level's (SCSI Core) interrupt routine, which
- * regains ownership of the SCSI command (de facto) from a LLDD, and enqueues
- * the command to the done queue for further processing.
+ * Description: This function is the mid-level's (SCSI Core) interrupt routine,
+ * which regains ownership of the SCSI command (de facto) from a LLDD, and
+ * enqueues the command to the done queue for further processing.
*
* This is the producer of the done queue who enqueues at the tail.
*
*/
static void scsi_done(struct scsi_cmnd *cmd)
{
- /*
- * We don't have to worry about this one timing out any more.
- * If we are unable to remove the timer, then the command
- * has already timed out. In which case, we have no choice but to
- * let the timeout function run, as we have no idea where in fact
- * that function could really be. It might be on another processor,
- * etc, etc.
- */
- if (!scsi_delete_timer(cmd))
- return;
- __scsi_done(cmd);
+ blk_complete_request(cmd->request);
}
-/* Private entry to scsi_done() to complete a command when the timer
- * isn't running --- used by scsi_times_out */
-void __scsi_done(struct scsi_cmnd *cmd)
+/* Move this to a header if it becomes more generally useful */
+static struct scsi_driver *scsi_cmd_to_driver(struct scsi_cmnd *cmd)
{
- struct request *rq = cmd->request;
-
- /*
- * Set the serial numbers back to zero
- */
- cmd->serial_number = 0;
-
- atomic_inc(&cmd->device->iodone_cnt);
- if (cmd->result)
- atomic_inc(&cmd->device->ioerr_cnt);
-
- BUG_ON(!rq);
-
- /*
- * The uptodate/nbytes values don't matter, as we allow partial
- * completes and thus will check this in the softirq callback
- */
- rq->completion_data = cmd;
- blk_complete_request(rq);
+ return *(struct scsi_driver **)cmd->request->rq_disk->private_data;
}
-/*
- * Function: scsi_finish_command
+/**
+ * scsi_finish_command - cleanup and pass command back to upper layer
+ * @cmd: the command
*
- * Purpose: Pass command off to upper layer for finishing of I/O
+ * Description: Pass command off to upper layer for finishing of I/O
* request, waking processes that are waiting on results,
* etc.
*/
{
struct scsi_device *sdev = cmd->device;
struct Scsi_Host *shost = sdev->host;
+ struct scsi_driver *drv;
+ unsigned int good_bytes;
scsi_device_unbusy(sdev);
"Notifying upper driver of completion "
"(result %x)\n", cmd->result));
- cmd->done(cmd);
+ good_bytes = scsi_bufflen(cmd);
+ if (cmd->request->cmd_type != REQ_TYPE_BLOCK_PC) {
+ int old_good_bytes = good_bytes;
+ drv = scsi_cmd_to_driver(cmd);
+ if (drv->done)
+ good_bytes = drv->done(cmd);
+ /*
+ * USB may not give sense identifying bad sector and
+ * simply return a residue instead, so subtract off the
+ * residue if drv->done() error processing indicates no
+ * change to the completion length.
+ */
+ if (good_bytes == old_good_bytes)
+ good_bytes -= scsi_get_resid(cmd);
+ }
+ scsi_io_completion(cmd, good_bytes);
}
EXPORT_SYMBOL(scsi_finish_command);
-/*
- * Function: scsi_adjust_queue_depth()
- *
- * Purpose: Allow low level drivers to tell us to change the queue depth
- * on a specific SCSI device
- *
- * Arguments: sdev - SCSI Device in question
- * tagged - Do we use tagged queueing (non-0) or do we treat
- * this device as an untagged device (0)
- * tags - Number of tags allowed if tagged queueing enabled,
- * or number of commands the low level driver can
- * queue up in non-tagged mode (as per cmd_per_lun).
+/**
+ * scsi_adjust_queue_depth - Let low level drivers change a device's queue depth
+ * @sdev: SCSI Device in question
+ * @tagged: Do we use tagged queueing (non-0) or do we treat
+ * this device as an untagged device (0)
+ * @tags: Number of tags allowed if tagged queueing enabled,
+ * or number of commands the low level driver can
+ * queue up in non-tagged mode (as per cmd_per_lun).
*
* Returns: Nothing
*
spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
- /* Check to see if the queue is managed by the block layer
- * if it is, and we fail to adjust the depth, exit */
- if (blk_queue_tagged(sdev->request_queue) &&
- blk_queue_resize_tags(sdev->request_queue, tags) != 0)
- goto out;
+ /*
+ * Check to see if the queue is managed by the block layer.
+ * If it is, and we fail to adjust the depth, exit.
+ *
+ * Do not resize the tag map if it is a host wide share bqt,
+ * because the size should be the hosts's can_queue. If there
+ * is more IO than the LLD's can_queue (so there are not enuogh
+ * tags) request_fn's host queue ready check will handle it.
+ */
+ if (!sdev->host->bqt) {
+ if (blk_queue_tagged(sdev->request_queue) &&
+ blk_queue_resize_tags(sdev->request_queue, tags) != 0)
+ goto out;
+ }
sdev->queue_depth = tags;
switch (tagged) {
}
EXPORT_SYMBOL(scsi_adjust_queue_depth);
-/*
- * Function: scsi_track_queue_full()
+/**
+ * scsi_track_queue_full - track QUEUE_FULL events to adjust queue depth
+ * @sdev: SCSI Device in question
+ * @depth: Current number of outstanding SCSI commands on this device,
+ * not counting the one returned as QUEUE_FULL.
*
- * Purpose: This function will track successive QUEUE_FULL events on a
+ * Description: This function will track successive QUEUE_FULL events on a
* specific SCSI device to determine if and when there is a
* need to adjust the queue depth on the device.
*
- * Arguments: sdev - SCSI Device in question
- * depth - Current number of outstanding SCSI commands on
- * this device, not counting the one returned as
- * QUEUE_FULL.
- *
- * Returns: 0 - No change needed
- * >0 - Adjust queue depth to this new depth
+ * Returns: 0 - No change needed, >0 - Adjust queue depth to this new depth,
* -1 - Drop back to untagged operation using host->cmd_per_lun
* as the untagged command depth
*
EXPORT_SYMBOL(scsi_track_queue_full);
/**
- * scsi_device_get - get an addition reference to a scsi_device
+ * scsi_device_get - get an additional reference to a scsi_device
* @sdev: device to get a reference to
*
- * Gets a reference to the scsi_device and increments the use count
+ * Description: Gets a reference to the scsi_device and increments the use count
* of the underlying LLDD module. You must hold host_lock of the
* parent Scsi_Host or already have a reference when calling this.
*/
* scsi_device_put - release a reference to a scsi_device
* @sdev: device to release a reference on.
*
- * Release a reference to the scsi_device and decrements the use count
- * of the underlying LLDD module. The device is freed once the last
+ * Description: Release a reference to the scsi_device and decrements the use
+ * count of the underlying LLDD module. The device is freed once the last
* user vanishes.
*/
void scsi_device_put(struct scsi_device *sdev)
}
EXPORT_SYMBOL(scsi_device_put);
-/* helper for shost_for_each_device, thus not documented */
+/* helper for shost_for_each_device, see that for documentation */
struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
struct scsi_device *prev)
{
/**
* starget_for_each_device - helper to walk all devices of a target
* @starget: target whose devices we want to iterate over.
+ * @data: Opaque passed to each function call.
+ * @fn: Function to call on each device
*
* This traverses over each device of @starget. The devices have
* a reference that must be released by scsi_host_put when breaking
EXPORT_SYMBOL(starget_for_each_device);
/**
- * __starget_for_each_device - helper to walk all devices of a target
- * (UNLOCKED)
+ * __starget_for_each_device - helper to walk all devices of a target (UNLOCKED)
* @starget: target whose devices we want to iterate over.
+ * @data: parameter for callback @fn()
+ * @fn: callback function that is invoked for each device
*
* This traverses over each device of @starget. It does _not_
* take a reference on the scsi_device, so the whole loop must be
* @starget: SCSI target pointer
* @lun: SCSI Logical Unit Number
*
- * Looks up the scsi_device with the specified @lun for a give
- * @starget. The returned scsi_device does not have an additional
+ * Description: Looks up the scsi_device with the specified @lun for a given
+ * @starget. The returned scsi_device does not have an additional
* reference. You must hold the host's host_lock over this call and
* any access to the returned scsi_device.
*
- * Note: The only reason why drivers would want to use this is because
- * they're need to access the device list in irq context. Otherwise you
+ * Note: The only reason why drivers should use this is because
+ * they need to access the device list in irq context. Otherwise you
* really want to use scsi_device_lookup_by_target instead.
**/
struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget,
* @starget: SCSI target pointer
* @lun: SCSI Logical Unit Number
*
- * Looks up the scsi_device with the specified @channel, @id, @lun for a
- * give host. The returned scsi_device has an additional reference that
- * needs to be release with scsi_host_put once you're done with it.
+ * Description: Looks up the scsi_device with the specified @channel, @id, @lun
+ * for a given host. The returned scsi_device has an additional reference that
+ * needs to be released with scsi_device_put once you're done with it.
**/
struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget,
uint lun)
EXPORT_SYMBOL(scsi_device_lookup_by_target);
/**
- * scsi_device_lookup - find a device given the host (UNLOCKED)
+ * __scsi_device_lookup - find a device given the host (UNLOCKED)
* @shost: SCSI host pointer
* @channel: SCSI channel (zero if only one channel)
- * @pun: SCSI target number (physical unit number)
+ * @id: SCSI target number (physical unit number)
* @lun: SCSI Logical Unit Number
*
- * Looks up the scsi_device with the specified @channel, @id, @lun for a
- * give host. The returned scsi_device does not have an additional reference.
- * You must hold the host's host_lock over this call and any access to the
- * returned scsi_device.
+ * Description: Looks up the scsi_device with the specified @channel, @id, @lun
+ * for a given host. The returned scsi_device does not have an additional
+ * reference. You must hold the host's host_lock over this call and any access
+ * to the returned scsi_device.
*
* Note: The only reason why drivers would want to use this is because
- * they're need to access the device list in irq context. Otherwise you
+ * they need to access the device list in irq context. Otherwise you
* really want to use scsi_device_lookup instead.
**/
struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost,
* @id: SCSI target number (physical unit number)
* @lun: SCSI Logical Unit Number
*
- * Looks up the scsi_device with the specified @channel, @id, @lun for a
- * give host. The returned scsi_device has an additional reference that
- * needs to be release with scsi_host_put once you're done with it.
+ * Description: Looks up the scsi_device with the specified @channel, @id, @lun
+ * for a given host. The returned scsi_device has an additional reference that
+ * needs to be released with scsi_device_put once you're done with it.
**/
struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost,
uint channel, uint id, uint lun)
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff