From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-Id: <20121228190352.897309171@decadent.org.uk> Date: Fri, 28 Dec 2012 20:05:18 +0100 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Sebastian Andrzej Siewior , Nicholas Bellinger Subject: [ 108/173] target/file: Fix 32-bit highmem breakage for SGL -> iovec mapping In-Reply-To: <20121228190330.025298996@decadent.org.uk> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Sebastian Andrzej Siewior commit 40ff2c3b3da35dd3a00ac6722056a59b4b3f2caf upstream. This patch changes vectored file I/O to use kmap + kunmap when mapping incoming SGL memory -> struct iovec in order to properly support 32-bit highmem configurations. This is because an extra bounce buffer may be required when processing scatterlist pages allocated with GFP_KERNEL. Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Nicholas Bellinger [bwh: Backported to 3.2: use task->task_sg{,_nents} for iteration] Signed-off-by: Ben Hutchings --- drivers/target/target_core_file.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) --- a/drivers/target/target_core_file.c +++ b/drivers/target/target_core_file.c @@ -300,7 +300,7 @@ static int fd_do_readv(struct se_task *t for_each_sg(task->task_sg, sg, task->task_sg_nents, i) { iov[i].iov_len = sg->length; - iov[i].iov_base = sg_virt(sg); + iov[i].iov_base = kmap(sg_page(sg)) + sg->offset; } old_fs = get_fs(); @@ -308,6 +308,8 @@ static int fd_do_readv(struct se_task *t ret = vfs_readv(fd, &iov[0], task->task_sg_nents, &pos); set_fs(old_fs); + for_each_sg(task->task_sg, sg, task->task_sg_nents, i) + kunmap(sg_page(sg)); kfree(iov); /* * Return zeros and GOOD status even if the READ did not return @@ -353,7 +355,7 @@ static int fd_do_writev(struct se_task * for_each_sg(task->task_sg, sg, task->task_sg_nents, i) { iov[i].iov_len = sg->length; - iov[i].iov_base = sg_virt(sg); + iov[i].iov_base = kmap(sg_page(sg)) + sg->offset; } old_fs = get_fs(); @@ -361,6 +363,9 @@ static int fd_do_writev(struct se_task * ret = vfs_writev(fd, &iov[0], task->task_sg_nents, &pos); set_fs(old_fs); + for_each_sg(task->task_sg, sg, task->task_sg_nents, i) + kunmap(sg_page(sg)); + kfree(iov); if (ret < 0 || ret != task->task_size) {