linux-kernel - [PATCH 11/21] target: Avoid mem leak and needless work in transport_generic_get

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Date:	Mon, 14 Mar 2011 04:06:05 -0700
From:	"Nicholas A. Bellinger" <nab@...ux-iscsi.org>
To:	linux-scsi <linux-scsi@...r.kernel.org>,
	linux-kernel <linux-kernel@...r.kernel.org>,
	James Bottomley <James.Bottomley@...senPartnership.com>
Cc:	Christoph Hellwig <hch@....de>,
	Mike Christie <michaelc@...wisc.edu>,
	Hannes Reinecke <hare@...e.de>,
	FUJITA Tomonori <fujita.tomonori@....ntt.co.jp>,
	Boaz Harrosh <bharrosh@...asas.com>,
	Joel Becker <jlbec@...lplan.org>,
	Stephen Rothwell <sfr@...b.auug.org.au>,
	Douglas Gilbert <dgilbert@...erlog.com>,
	Jesper Juhl <jj@...osbits.net>,
	"Nicholas A. Bellinger" <nab@...ux-iscsi.org>
Subject: [PATCH 11/21] target: Avoid mem leak and needless work in transport_generic_get_mem

From: Jesper Juhl <jj@...osbits.net>

In drivers/target/target_core_transport.c::transport_generic_get_mem()
there are a few potential memory leaks in the error paths. This patch
makes sure that we free previously allocated memory when other allocations
fail.  It also moves some work (INIT_LIST_HEAD() and assignment to
se_mem->se_len) below all the allocations so that if something fails we
don't do the work at all.

Signed-off-by: Jesper Juhl <jj@...osbits.net>
Signed-off-by: Nicholas A. Bellinger <nab@...ux-iscsi.org>
---
 drivers/target/target_core_transport.c |    9 ++++++---
 1 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index 30c1223..af56ce2 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -4358,11 +4358,9 @@ transport_generic_get_mem(struct se_cmd *cmd, u32 length, u32 dma_size)
 			printk(KERN_ERR "Unable to allocate struct se_mem\n");
 			goto out;
 		}
-		INIT_LIST_HEAD(&se_mem->se_list);
-		se_mem->se_len = (length > dma_size) ? dma_size : length;
 
 /* #warning FIXME Allocate contigous pages for struct se_mem elements */
-		se_mem->se_page = (struct page *) alloc_pages(GFP_KERNEL, 0);
+		se_mem->se_page = alloc_pages(GFP_KERNEL, 0);
 		if (!(se_mem->se_page)) {
 			printk(KERN_ERR "alloc_pages() failed\n");
 			goto out;
@@ -4373,6 +4371,8 @@ transport_generic_get_mem(struct se_cmd *cmd, u32 length, u32 dma_size)
 			printk(KERN_ERR "kmap_atomic() failed\n");
 			goto out;
 		}
+		INIT_LIST_HEAD(&se_mem->se_list);
+		se_mem->se_len = (length > dma_size) ? dma_size : length;
 		memset(buf, 0, se_mem->se_len);
 		kunmap_atomic(buf, KM_IRQ0);
 
@@ -4391,6 +4391,9 @@ transport_generic_get_mem(struct se_cmd *cmd, u32 length, u32 dma_size)
 
 	return 0;
 out:
+	if (se_mem)
+		__free_pages(se_mem->se_page, 0);
+	kmem_cache_free(se_mem_cache, se_mem);
 	return -1;
 }
 
-- 
1.7.4.1

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