[PATCH 21/26] cciss: sanitize max commands
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From: Stephen M. Cameron on 19 Jul 2010 14:50 From: Stephen M. Cameron <scameron(a)beardog.cce.hp.com> 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(a)beardog.cce.hp.com> --- drivers/block/cciss.c | 14 +++++++++++++- 1 files changed, 13 insertions(+), 1 deletions(-) diff --git a/drivers/block/cciss.c b/drivers/block/cciss.c index b3060ec..6d4c4f2 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)); /* -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |