lkml.org 
[lkml]   [2008]   [Aug]   [25]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 1/2] bio: fix bio_copy_kern() handling of bio->bv_len
Date
The commit 68154e90c9d1492d570671ae181d9a8f8530da55 introduced
bio_copy_kern() to add bounce support to blk_rq_map_kern.

bio_copy_kern() uses bio->bv_len to copy data for READ commands after
the completion but it doesn't work with a request that partially
completed. SCSI always completes a PC request as a whole but seems
some don't.

This patch fixes bio_copy_kern to handle the above case. As
bio_copy_user does, bio_copy_kern uses struct bio_map_data to store
struct bio_vec.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Reported-by: Nix <nix@esperi.org.uk>
Tested-by: Nix <nix@esperi.org.uk>
Cc: stable@kernel.org
---
fs/bio.c | 38 ++++++++++++++++++++++++++++----------
1 files changed, 28 insertions(+), 10 deletions(-)

diff --git a/fs/bio.c b/fs/bio.c
index 8000e2f..8b1f5ee 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -469,20 +469,21 @@ static void bio_free_map_data(struct bio_map_data *bmd)
kfree(bmd);
}

-static struct bio_map_data *bio_alloc_map_data(int nr_segs, int iov_count)
+static struct bio_map_data *bio_alloc_map_data(int nr_segs, int iov_count,
+ gfp_t gfp_mask)
{
- struct bio_map_data *bmd = kmalloc(sizeof(*bmd), GFP_KERNEL);
+ struct bio_map_data *bmd = kmalloc(sizeof(*bmd), gfp_mask);

if (!bmd)
return NULL;

- bmd->iovecs = kmalloc(sizeof(struct bio_vec) * nr_segs, GFP_KERNEL);
+ bmd->iovecs = kmalloc(sizeof(struct bio_vec) * nr_segs, gfp_mask);
if (!bmd->iovecs) {
kfree(bmd);
return NULL;
}

- bmd->sgvecs = kmalloc(sizeof(struct sg_iovec) * iov_count, GFP_KERNEL);
+ bmd->sgvecs = kmalloc(sizeof(struct sg_iovec) * iov_count, gfp_mask);
if (bmd->sgvecs)
return bmd;

@@ -596,7 +597,7 @@ struct bio *bio_copy_user_iov(struct request_queue *q, struct sg_iovec *iov,
len += iov[i].iov_len;
}

- bmd = bio_alloc_map_data(nr_pages, iov_count);
+ bmd = bio_alloc_map_data(nr_pages, iov_count, GFP_KERNEL);
if (!bmd)
return ERR_PTR(-ENOMEM);

@@ -942,19 +943,22 @@ static void bio_copy_kern_endio(struct bio *bio, int err)
{
struct bio_vec *bvec;
const int read = bio_data_dir(bio) == READ;
- char *p = bio->bi_private;
+ struct bio_map_data *bmd = bio->bi_private;
int i;
+ char *p = bmd->sgvecs[0].iov_base;

__bio_for_each_segment(bvec, bio, i, 0) {
char *addr = page_address(bvec->bv_page);
+ int len = bmd->iovecs[i].bv_len;

if (read && !err)
- memcpy(p, addr, bvec->bv_len);
+ memcpy(p, addr, len);

__free_page(bvec->bv_page);
- p += bvec->bv_len;
+ p += len;
}

+ bio_free_map_data(bmd);
bio_put(bio);
}

@@ -978,11 +982,21 @@ struct bio *bio_copy_kern(struct request_queue *q, void *data, unsigned int len,
const int nr_pages = end - start;
struct bio *bio;
struct bio_vec *bvec;
+ struct bio_map_data *bmd;
int i, ret;
+ struct sg_iovec iov;
+
+ iov.iov_base = data;
+ iov.iov_len = len;
+
+ bmd = bio_alloc_map_data(nr_pages, 1, gfp_mask);
+ if (!bmd)
+ return ERR_PTR(-ENOMEM);

+ ret = -ENOMEM;
bio = bio_alloc(gfp_mask, nr_pages);
if (!bio)
- return ERR_PTR(-ENOMEM);
+ goto out_bmd;

while (len) {
struct page *page;
@@ -1016,14 +1030,18 @@ struct bio *bio_copy_kern(struct request_queue *q, void *data, unsigned int len,
}
}

- bio->bi_private = data;
+ bio->bi_private = bmd;
bio->bi_end_io = bio_copy_kern_endio;
+
+ bio_set_map_data(bmd, bio, &iov, 1);
return bio;
cleanup:
bio_for_each_segment(bvec, bio, i)
__free_page(bvec->bv_page);

bio_put(bio);
+out_bmd:
+ bio_free_map_data(bmd);

return ERR_PTR(ret);
}
--
1.5.5.GIT


\
 
 \ /
  Last update: 2008-08-25 07:37    [W:0.056 / U:6.792 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site