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authorStephen M. Cameron <scameron@beardog.cce.hp.com>2010-07-19 13:46:28 -0500
committerJens Axboe <jaxboe@fusionio.com>2010-08-07 18:52:30 +0200
commitadfbc1ff342ece2e482254bcc5381fadfffbbb89 (patch)
treeaefa1482a22f0378a1397546595e7980fb4acf75 /drivers/block/cciss.c
parenta6528d017234b483283274fbdd360f3541befe19 (diff)
cciss: sanitize max commands
cciss: sanitize max commands Some controllers might try to tell us they support 0 commands in performant mode. This is a lie told by buggy firmware. We have to be wary of this lest we try to allocate a negative number of command blocks, which will be treated as unsigned, and get an out of memory condition. Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Diffstat (limited to 'drivers/block/cciss.c')
-rw-r--r--drivers/block/cciss.c14
1 files changed, 13 insertions, 1 deletions
diff --git a/drivers/block/cciss.c b/drivers/block/cciss.c
index b3060eced55..6d4c4f227d5 100644
--- a/drivers/block/cciss.c
+++ b/drivers/block/cciss.c
@@ -4112,13 +4112,25 @@ static int __devinit cciss_find_cfgtables(ctlr_info_t *h)
return 0;
}
+static void __devinit cciss_get_max_perf_mode_cmds(struct ctlr_info *h)
+{
+ h->max_commands = readl(&(h->cfgtable->MaxPerformantModeCommands));
+ if (h->max_commands < 16) {
+ dev_warn(&h->pdev->dev, "Controller reports "
+ "max supported commands of %d, an obvious lie. "
+ "Using 16. Ensure that firmware is up to date.\n",
+ h->max_commands);
+ h->max_commands = 16;
+ }
+}
+
/* Interrogate the hardware for some limits:
* max commands, max SG elements without chaining, and with chaining,
* SG chain block size, etc.
*/
static void __devinit cciss_find_board_params(ctlr_info_t *h)
{
- h->max_commands = readl(&(h->cfgtable->MaxPerformantModeCommands));
+ cciss_get_max_perf_mode_cmds(h);
h->nr_cmds = h->max_commands - 4; /* Allow room for some ioctls */
h->maxsgentries = readl(&(h->cfgtable->MaxSGElements));
/*