X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=block%2Fblk-settings.c;h=f5ed5a1187ba8564527b70f682328b31eea4549a;hb=b2e75eff5e859d0c294e7405958362b26a423c6e;hp=e14fcbcedbfa47584e2162e00dc2307972c4ec64;hpb=9504e0864b58b4a304820dcf3755f1da80d5e72f;p=safe%2Fjmp%2Flinux-2.6 diff --git a/block/blk-settings.c b/block/blk-settings.c index e14fcbc..f5ed5a1 100644 --- a/block/blk-settings.c +++ b/block/blk-settings.c @@ -8,7 +8,9 @@ #include #include /* for max_pfn/max_low_pfn */ #include +#include #include +#include #include "blk.h" @@ -91,10 +93,9 @@ EXPORT_SYMBOL_GPL(blk_queue_lld_busy); */ void blk_set_default_limits(struct queue_limits *lim) { - lim->max_phys_segments = MAX_PHYS_SEGMENTS; - lim->max_hw_segments = MAX_HW_SEGMENTS; + lim->max_segments = BLK_MAX_SEGMENTS; lim->seg_boundary_mask = BLK_SEG_BOUNDARY_MASK; - lim->max_segment_size = MAX_SEGMENT_SIZE; + lim->max_segment_size = BLK_MAX_SEGMENT_SIZE; lim->max_sectors = BLK_DEF_MAX_SECTORS; lim->max_hw_sectors = INT_MAX; lim->max_discard_sectors = 0; @@ -154,7 +155,7 @@ void blk_queue_make_request(struct request_queue *q, make_request_fn *mfn) q->unplug_timer.data = (unsigned long)q; blk_set_default_limits(&q->limits); - blk_queue_max_sectors(q, SAFE_MAX_SECTORS); + blk_queue_max_hw_sectors(q, BLK_SAFE_MAX_SECTORS); /* * If the caller didn't supply a lock, fall back to our embedded @@ -210,37 +211,32 @@ void blk_queue_bounce_limit(struct request_queue *q, u64 dma_mask) EXPORT_SYMBOL(blk_queue_bounce_limit); /** - * blk_queue_max_sectors - set max sectors for a request for this queue + * blk_queue_max_hw_sectors - set max sectors for a request for this queue * @q: the request queue for the device - * @max_sectors: max sectors in the usual 512b unit + * @max_hw_sectors: max hardware sectors in the usual 512b unit * * Description: - * Enables a low level driver to set an upper limit on the size of - * received requests. + * Enables a low level driver to set a hard upper limit, + * max_hw_sectors, on the size of requests. max_hw_sectors is set by + * the device driver based upon the combined capabilities of I/O + * controller and storage device. + * + * max_sectors is a soft limit imposed by the block layer for + * filesystem type requests. This value can be overridden on a + * per-device basis in /sys/block//queue/max_sectors_kb. + * The soft limit can not exceed max_hw_sectors. **/ -void blk_queue_max_sectors(struct request_queue *q, unsigned int max_sectors) +void blk_queue_max_hw_sectors(struct request_queue *q, unsigned int max_hw_sectors) { - if ((max_sectors << 9) < PAGE_CACHE_SIZE) { - max_sectors = 1 << (PAGE_CACHE_SHIFT - 9); + if ((max_hw_sectors << 9) < PAGE_CACHE_SIZE) { + max_hw_sectors = 1 << (PAGE_CACHE_SHIFT - 9); printk(KERN_INFO "%s: set to minimum %d\n", - __func__, max_sectors); - } - - if (BLK_DEF_MAX_SECTORS > max_sectors) - q->limits.max_hw_sectors = q->limits.max_sectors = max_sectors; - else { - q->limits.max_sectors = BLK_DEF_MAX_SECTORS; - q->limits.max_hw_sectors = max_sectors; + __func__, max_hw_sectors); } -} -EXPORT_SYMBOL(blk_queue_max_sectors); -void blk_queue_max_hw_sectors(struct request_queue *q, unsigned int max_sectors) -{ - if (BLK_DEF_MAX_SECTORS > max_sectors) - q->limits.max_hw_sectors = BLK_DEF_MAX_SECTORS; - else - q->limits.max_hw_sectors = max_sectors; + q->limits.max_hw_sectors = max_hw_sectors; + q->limits.max_sectors = min_t(unsigned int, max_hw_sectors, + BLK_DEF_MAX_SECTORS); } EXPORT_SYMBOL(blk_queue_max_hw_sectors); @@ -257,41 +253,15 @@ void blk_queue_max_discard_sectors(struct request_queue *q, EXPORT_SYMBOL(blk_queue_max_discard_sectors); /** - * blk_queue_max_phys_segments - set max phys segments for a request for this queue - * @q: the request queue for the device - * @max_segments: max number of segments - * - * Description: - * Enables a low level driver to set an upper limit on the number of - * physical data segments in a request. This would be the largest sized - * scatter list the driver could handle. - **/ -void blk_queue_max_phys_segments(struct request_queue *q, - unsigned short max_segments) -{ - if (!max_segments) { - max_segments = 1; - printk(KERN_INFO "%s: set to minimum %d\n", - __func__, max_segments); - } - - q->limits.max_phys_segments = max_segments; -} -EXPORT_SYMBOL(blk_queue_max_phys_segments); - -/** - * blk_queue_max_hw_segments - set max hw segments for a request for this queue + * blk_queue_max_segments - set max hw segments for a request for this queue * @q: the request queue for the device * @max_segments: max number of segments * * Description: * Enables a low level driver to set an upper limit on the number of - * hw data segments in a request. This would be the largest number of - * address/length pairs the host adapter can actually give at once - * to the device. + * hw data segments in a request. **/ -void blk_queue_max_hw_segments(struct request_queue *q, - unsigned short max_segments) +void blk_queue_max_segments(struct request_queue *q, unsigned short max_segments) { if (!max_segments) { max_segments = 1; @@ -299,9 +269,9 @@ void blk_queue_max_hw_segments(struct request_queue *q, __func__, max_segments); } - q->limits.max_hw_segments = max_segments; + q->limits.max_segments = max_segments; } -EXPORT_SYMBOL(blk_queue_max_hw_segments); +EXPORT_SYMBOL(blk_queue_max_segments); /** * blk_queue_max_segment_size - set max segment size for blk_rq_map_sg @@ -493,32 +463,31 @@ void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b) } EXPORT_SYMBOL(blk_queue_stack_limits); -static unsigned int lcm(unsigned int a, unsigned int b) -{ - if (a && b) - return (a * b) / gcd(a, b); - else if (b) - return b; - - return a; -} - /** * blk_stack_limits - adjust queue_limits for stacked devices - * @t: the stacking driver limits (top) - * @b: the underlying queue limits (bottom) - * @offset: offset to beginning of data within component device + * @t: the stacking driver limits (top device) + * @b: the underlying queue limits (bottom, component device) + * @start: first data sector within component device * * Description: - * Merges two queue_limit structs. Returns 0 if alignment didn't - * change. Returns -1 if adding the bottom device caused - * misalignment. + * This function is used by stacking drivers like MD and DM to ensure + * that all component devices have compatible block sizes and + * alignments. The stacking driver must provide a queue_limits + * struct (top) and then iteratively call the stacking function for + * all component (bottom) devices. The stacking function will + * attempt to combine the values and ensure proper alignment. + * + * Returns 0 if the top and bottom queue_limits are compatible. The + * top device's block sizes and alignment offsets may be adjusted to + * ensure alignment with the bottom device. If no compatible sizes + * and alignments exist, -1 is returned and the resulting top + * queue_limits will have the misaligned flag set to indicate that + * the alignment_offset is undefined. */ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b, - sector_t offset) + sector_t start) { - sector_t alignment; - unsigned int top, bottom, granularity; + unsigned int top, bottom, alignment, ret = 0; t->max_sectors = min_not_zero(t->max_sectors, b->max_sectors); t->max_hw_sectors = min_not_zero(t->max_hw_sectors, b->max_hw_sectors); @@ -527,26 +496,29 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b, t->seg_boundary_mask = min_not_zero(t->seg_boundary_mask, b->seg_boundary_mask); - t->max_phys_segments = min_not_zero(t->max_phys_segments, - b->max_phys_segments); - - t->max_hw_segments = min_not_zero(t->max_hw_segments, - b->max_hw_segments); + t->max_segments = min_not_zero(t->max_segments, b->max_segments); t->max_segment_size = min_not_zero(t->max_segment_size, b->max_segment_size); - granularity = max(b->physical_block_size, b->io_min); - alignment = b->alignment_offset - (offset & (granularity - 1)); + t->misaligned |= b->misaligned; + alignment = queue_limit_alignment_offset(b, start); + + /* Bottom device has different alignment. Check that it is + * compatible with the current top alignment. + */ if (t->alignment_offset != alignment) { top = max(t->physical_block_size, t->io_min) + t->alignment_offset; - bottom = granularity + alignment; + bottom = max(b->physical_block_size, b->io_min) + alignment; - if (max(top, bottom) & (min(top, bottom) - 1)) + /* Verify that top and bottom intervals line up */ + if (max(top, bottom) & (min(top, bottom) - 1)) { t->misaligned = 1; + ret = -1; + } } t->logical_block_size = max(t->logical_block_size, @@ -561,32 +533,40 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b, t->no_cluster |= b->no_cluster; t->discard_zeroes_data &= b->discard_zeroes_data; + /* Physical block size a multiple of the logical block size? */ if (t->physical_block_size & (t->logical_block_size - 1)) { t->physical_block_size = t->logical_block_size; t->misaligned = 1; + ret = -1; } + /* Minimum I/O a multiple of the physical block size? */ if (t->io_min & (t->physical_block_size - 1)) { t->io_min = t->physical_block_size; t->misaligned = 1; + ret = -1; } + /* Optimal I/O a multiple of the physical block size? */ if (t->io_opt & (t->physical_block_size - 1)) { t->io_opt = 0; t->misaligned = 1; + ret = -1; } + /* Find lowest common alignment_offset */ t->alignment_offset = lcm(t->alignment_offset, alignment) & (max(t->physical_block_size, t->io_min) - 1); - if (t->alignment_offset & (t->logical_block_size - 1)) + /* Verify that new alignment_offset is on a logical block boundary */ + if (t->alignment_offset & (t->logical_block_size - 1)) { t->misaligned = 1; + ret = -1; + } /* Discard alignment and granularity */ if (b->discard_granularity) { - - alignment = b->discard_alignment - - (offset & (b->discard_granularity - 1)); + alignment = queue_limit_discard_alignment(b, start); if (t->discard_granularity != 0 && t->discard_alignment != alignment) { @@ -598,26 +578,49 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b, t->discard_misaligned = 1; } + t->max_discard_sectors = min_not_zero(t->max_discard_sectors, + b->max_discard_sectors); t->discard_granularity = max(t->discard_granularity, b->discard_granularity); t->discard_alignment = lcm(t->discard_alignment, alignment) & (t->discard_granularity - 1); } - return t->misaligned ? -1 : 0; + return ret; } EXPORT_SYMBOL(blk_stack_limits); /** + * bdev_stack_limits - adjust queue limits for stacked drivers + * @t: the stacking driver limits (top device) + * @bdev: the component block_device (bottom) + * @start: first data sector within component device + * + * Description: + * Merges queue limits for a top device and a block_device. Returns + * 0 if alignment didn't change. Returns -1 if adding the bottom + * device caused misalignment. + */ +int bdev_stack_limits(struct queue_limits *t, struct block_device *bdev, + sector_t start) +{ + struct request_queue *bq = bdev_get_queue(bdev); + + start += get_start_sect(bdev); + + return blk_stack_limits(t, &bq->limits, start); +} +EXPORT_SYMBOL(bdev_stack_limits); + +/** * disk_stack_limits - adjust queue limits for stacked drivers * @disk: MD/DM gendisk (top) * @bdev: the underlying block device (bottom) * @offset: offset to beginning of data within component device * * Description: - * Merges the limits for two queues. Returns 0 if alignment - * didn't change. Returns -1 if adding the bottom device caused - * misalignment. + * Merges the limits for a top level gendisk and a bottom level + * block_device. */ void disk_stack_limits(struct gendisk *disk, struct block_device *bdev, sector_t offset) @@ -625,9 +628,7 @@ void disk_stack_limits(struct gendisk *disk, struct block_device *bdev, struct request_queue *t = disk->queue; struct request_queue *b = bdev_get_queue(bdev); - offset += get_start_sect(bdev) << 9; - - if (blk_stack_limits(&t->limits, &b->limits, offset) < 0) { + if (bdev_stack_limits(&t->limits, bdev, offset >> 9) < 0) { char top[BDEVNAME_SIZE], bottom[BDEVNAME_SIZE]; disk_name(disk, 0, top); @@ -699,22 +700,19 @@ EXPORT_SYMBOL(blk_queue_update_dma_pad); * does is adjust the queue so that the buf is always appended * silently to the scatterlist. * - * Note: This routine adjusts max_hw_segments to make room for - * appending the drain buffer. If you call - * blk_queue_max_hw_segments() or blk_queue_max_phys_segments() after - * calling this routine, you must set the limit to one fewer than your - * device can support otherwise there won't be room for the drain - * buffer. + * Note: This routine adjusts max_hw_segments to make room for appending + * the drain buffer. If you call blk_queue_max_segments() after calling + * this routine, you must set the limit to one fewer than your device + * can support otherwise there won't be room for the drain buffer. */ int blk_queue_dma_drain(struct request_queue *q, dma_drain_needed_fn *dma_drain_needed, void *buf, unsigned int size) { - if (queue_max_hw_segments(q) < 2 || queue_max_phys_segments(q) < 2) + if (queue_max_segments(q) < 2) return -EINVAL; /* make room for appending the drain */ - blk_queue_max_hw_segments(q, queue_max_hw_segments(q) - 1); - blk_queue_max_phys_segments(q, queue_max_phys_segments(q) - 1); + blk_queue_max_segments(q, queue_max_segments(q) - 1); q->dma_drain_needed = dma_drain_needed; q->dma_drain_buffer = buf; q->dma_drain_size = size;