From 7a3cf6ca1ab2a2f7161c6dec5a787fc7a5de864e Mon Sep 17 00:00:00 2001 From: Nicholas Bellinger Date: Thu, 31 Jan 2013 15:05:48 -0800 Subject: [PATCH] target: Fix divide by zero bug in fabric_max_sectors for unconfigured devices This patch fixes a possible divide by zero bug when the fabric_max_sectors device attribute is written and backend se_device failed to be successfully configured -> enabled. Go ahead and use block_size=512 within se_dev_set_fabric_max_sectors() in the event of a target_configure_device() failure case, as no valid dev->dev_attrib.block_size value will have been setup yet. Cc: stable@vger.kernel.org Signed-off-by: Nicholas Bellinger --- drivers/target/target_core_device.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c index e2695101bb99..f2aa7543d20a 100644 --- a/drivers/target/target_core_device.c +++ b/drivers/target/target_core_device.c @@ -941,6 +941,8 @@ int se_dev_set_queue_depth(struct se_device *dev, u32 queue_depth) int se_dev_set_fabric_max_sectors(struct se_device *dev, u32 fabric_max_sectors) { + int block_size = dev->dev_attrib.block_size; + if (dev->export_count) { pr_err("dev[%p]: Unable to change SE Device" " fabric_max_sectors while export_count is %d\n", @@ -978,8 +980,12 @@ int se_dev_set_fabric_max_sectors(struct se_device *dev, u32 fabric_max_sectors) /* * Align max_sectors down to PAGE_SIZE to follow transport_allocate_data_tasks() */ + if (!block_size) { + block_size = 512; + pr_warn("Defaulting to 512 for zero block_size\n"); + } fabric_max_sectors = se_dev_align_max_sectors(fabric_max_sectors, - dev->dev_attrib.block_size); + block_size); dev->dev_attrib.fabric_max_sectors = fabric_max_sectors; pr_debug("dev[%p]: SE Device max_sectors changed to %u\n",