[PATCH] IB/mthca: Initialize eq->nent before we use it

In mthca_create_eq(), we call get_eqe() before setting eq->nent.  This
is wrong, because get_eqe() uses eq->nent.  Fix this, and clean up the
code a little while we're at it.  (We got lucky with the current code,
because eq->nent was cleared to 0, which get_eqe() made happen to do
the right thing)

Pointed out by Michael S. Tsirkin <mst@mellanox.co.il>

Signed-off-by: Roland Dreier <rolandd@cisco.com>

diff --git a/drivers/infiniband/hw/mthca/mthca_eq.c b/drivers/infiniband/hw/mthca/mthca_eq.c
index 18f0981..78152a8 100644 (file)
--- a/drivers/infiniband/hw/mthca/mthca_eq.c
+++ b/drivers/infiniband/hw/mthca/mthca_eq.c
@@ -476,12 +476,8 @@ static int __devinit mthca_create_eq(struct mthca_dev *dev,
        int i;
        u8 status;
 
-       /* Make sure EQ size is aligned to a power of 2 size. */
-       for (i = 1; i < nent; i <<= 1)
-               ; /* nothing */
-       nent = i;
-
-       eq->dev = dev;
+       eq->dev  = dev;
+       eq->nent = roundup_pow_of_two(max(nent, 2));
 
        eq->page_list = kmalloc(npages * sizeof *eq->page_list,
                                GFP_KERNEL);
@@ -512,7 +508,7 @@ static int __devinit mthca_create_eq(struct mthca_dev *dev,
                memset(eq->page_list[i].buf, 0, PAGE_SIZE);
        }
 
-       for (i = 0; i < nent; ++i)
+       for (i = 0; i < eq->nent; ++i)
                set_eqe_hw(get_eqe(eq, i));
 
        eq->eqn = mthca_alloc(&dev->eq_table.alloc);
@@ -528,8 +524,6 @@ static int __devinit mthca_create_eq(struct mthca_dev *dev,
        if (err)
                goto err_out_free_eq;
 
-       eq->nent = nent;
-
        memset(eq_context, 0, sizeof *eq_context);
        eq_context->flags           = cpu_to_be32(MTHCA_EQ_STATUS_OK   |
                                                  MTHCA_EQ_OWNER_HW    |
@@ -538,7 +532,7 @@ static int __devinit mthca_create_eq(struct mthca_dev *dev,
        if (mthca_is_memfree(dev))
                eq_context->flags  |= cpu_to_be32(MTHCA_EQ_STATE_ARBEL);
 
-       eq_context->logsize_usrpage = cpu_to_be32((ffs(nent) - 1) << 24);
+       eq_context->logsize_usrpage = cpu_to_be32((ffs(eq->nent) - 1) << 24);
        if (mthca_is_memfree(dev)) {
                eq_context->arbel_pd = cpu_to_be32(dev->driver_pd.pd_num);
        } else {
@@ -569,7 +563,7 @@ static int __devinit mthca_create_eq(struct mthca_dev *dev,
        dev->eq_table.arm_mask |= eq->eqn_mask;
 
        mthca_dbg(dev, "Allocated EQ %d with %d entries\n",
-                 eq->eqn, nent);
+                 eq->eqn, eq->nent);
 
        return err;