From bdfb3335569583fd195a3a1a89380d7648a9a85f Mon Sep 17 00:00:00 2001 From: Nicholas Bellinger Date: Tue, 19 Feb 2013 03:15:14 +0000 Subject: [PATCH] target: Fix divide by zero bug in fabric_max_sectors for unconfigured devices commit 7a3cf6ca1ab2a2f7161c6dec5a787fc7a5de864e upstream 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. Signed-off-by: Nicholas Bellinger Cc: Herton Ronaldo Krzesinski Signed-off-by: Greg Kroah-Hartman --- 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 26c62f05975..4ecf9d61c22 100644 --- a/drivers/target/target_core_device.c +++ b/drivers/target/target_core_device.c @@ -1230,6 +1230,8 @@ int se_dev_set_max_sectors(struct se_device *dev, u32 max_sectors) int se_dev_set_fabric_max_sectors(struct se_device *dev, u32 fabric_max_sectors) { + int block_size = dev->se_sub_dev->se_dev_attrib.block_size; + if (atomic_read(&dev->dev_export_obj.obj_access_count)) { pr_err("dev[%p]: Unable to change SE Device" " fabric_max_sectors while dev_export_obj: %d count exists\n", @@ -1267,8 +1269,12 @@ 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->se_sub_dev->se_dev_attrib.block_size); + block_size); dev->se_sub_dev->se_dev_attrib.fabric_max_sectors = fabric_max_sectors; pr_debug("dev[%p]: SE Device max_sectors changed to %u\n", -- 2.34.1