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Message-Id: <1421409895-21377-4-git-send-email-hch@lst.de>
Date: Fri, 16 Jan 2015 13:04:51 +0100
From: Christoph Hellwig <hch@....de>
To: Jens Axboe <axboe@...nel.dk>,
Dongsu Park <dongsu.park@...fitbricks.com>
Cc: Kent Overstreet <kmo@...erainc.com>, linux-kernel@...r.kernel.org
Subject: [PATCH 3/7] block: add a helper to free bio bounce buffer pages
The code sniplet to walk all bio_vecs and free their pages is opencoded in
way to many places, so factor it into a helper. Also convert the slightly
more complex cases in bio_kern_endio and __bio_copy_iov where we break
the freeing from an existing loop into a separate one.
Signed-off-by: Christoph Hellwig <hch@....de>
---
block/bio.c | 65 +++++++++++++++++++++++++++++++------------------------------
1 file changed, 33 insertions(+), 32 deletions(-)
diff --git a/block/bio.c b/block/bio.c
index 879921e..0895f69 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -1048,7 +1048,7 @@ static struct bio_map_data *bio_alloc_map_data(unsigned int iov_count,
}
static int __bio_copy_iov(struct bio *bio, const struct sg_iovec *iov, int iov_count,
- int to_user, int from_user, int do_free_page)
+ int to_user, int from_user)
{
int ret = 0, i;
struct bio_vec *bvec;
@@ -1090,14 +1090,20 @@ static int __bio_copy_iov(struct bio *bio, const struct sg_iovec *iov, int iov_c
iov_off = 0;
}
}
-
- if (do_free_page)
- __free_page(bvec->bv_page);
}
return ret;
}
+static void bio_free_pages(struct bio *bio)
+{
+ struct bio_vec *bvec;
+ int i;
+
+ bio_for_each_segment_all(bvec, bio, i)
+ __free_page(bvec->bv_page);
+}
+
/**
* bio_uncopy_user - finish previously mapped bio
* @bio: bio being terminated
@@ -1108,8 +1114,7 @@ static int __bio_copy_iov(struct bio *bio, const struct sg_iovec *iov, int iov_c
int bio_uncopy_user(struct bio *bio)
{
struct bio_map_data *bmd = bio->bi_private;
- struct bio_vec *bvec;
- int ret = 0, i;
+ int ret = 0;
if (!bio_flagged(bio, BIO_NULL_MAPPED)) {
/*
@@ -1118,11 +1123,9 @@ int bio_uncopy_user(struct bio *bio)
*/
if (current->mm)
ret = __bio_copy_iov(bio, bmd->sgvecs, bmd->nr_sgvecs,
- bio_data_dir(bio) == READ,
- 0, bmd->is_our_pages);
- else if (bmd->is_our_pages)
- bio_for_each_segment_all(bvec, bio, i)
- __free_page(bvec->bv_page);
+ bio_data_dir(bio) == READ, 0);
+ if (bmd->is_our_pages)
+ bio_free_pages(bio);
}
kfree(bmd);
bio_put(bio);
@@ -1149,7 +1152,6 @@ struct bio *bio_copy_user_iov(struct request_queue *q,
int write_to_vm, gfp_t gfp_mask)
{
struct bio_map_data *bmd;
- struct bio_vec *bvec;
struct page *page;
struct bio *bio;
int i, ret;
@@ -1238,7 +1240,7 @@ struct bio *bio_copy_user_iov(struct request_queue *q,
*/
if ((!write_to_vm && (!map_data || !map_data->null_mapped)) ||
(map_data && map_data->from_user)) {
- ret = __bio_copy_iov(bio, iov, iov_count, 0, 1, 0);
+ ret = __bio_copy_iov(bio, iov, iov_count, 0, 1);
if (ret)
goto cleanup;
}
@@ -1247,9 +1249,7 @@ struct bio *bio_copy_user_iov(struct request_queue *q,
return bio;
cleanup:
if (!map_data)
- bio_for_each_segment_all(bvec, bio, i)
- __free_page(bvec->bv_page);
-
+ bio_free_pages(bio);
bio_put(bio);
out_bmd:
kfree(bmd);
@@ -1510,22 +1510,22 @@ EXPORT_SYMBOL(bio_map_kern);
static void bio_copy_kern_endio(struct bio *bio, int err)
{
- struct bio_vec *bvec;
- const int read = bio_data_dir(bio) == READ;
+ bio_free_pages(bio);
+ bio_put(bio);
+}
+
+static void bio_copy_kern_endio_read(struct bio *bio, int err)
+{
char *p = bio->bi_private;
+ struct bio_vec *bvec;
int i;
bio_for_each_segment_all(bvec, bio, i) {
- char *addr = page_address(bvec->bv_page);
-
- if (read)
- memcpy(p, addr, bvec->bv_len);
-
- __free_page(bvec->bv_page);
+ memcpy(p, page_address(bvec->bv_page), bvec->bv_len);
p += bvec->bv_len;
}
- bio_put(bio);
+ bio_copy_kern_endio(bio, err);
}
/**
@@ -1545,10 +1545,9 @@ struct bio *bio_copy_kern(struct request_queue *q, void *data, unsigned int len,
unsigned long kaddr = (unsigned long)data;
unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
unsigned long start = kaddr >> PAGE_SHIFT;
- struct bio_vec *bvec;
struct bio *bio;
void *p = data;
- int nr_pages = 0, i;
+ int nr_pages = 0;
/*
* Overflow, abort
@@ -1582,16 +1581,18 @@ struct bio *bio_copy_kern(struct request_queue *q, void *data, unsigned int len,
p += bytes;
}
- if (!reading)
+ if (reading) {
+ bio->bi_end_io = bio_copy_kern_endio_read;
+ bio->bi_private = data;
+ } else {
+ bio->bi_end_io = bio_copy_kern_endio;
bio->bi_rw |= REQ_WRITE;
+ }
- bio->bi_private = data;
- bio->bi_end_io = bio_copy_kern_endio;
return bio;
cleanup:
- bio_for_each_segment_all(bvec, bio, i)
- __free_page(bvec->bv_page);
+ bio_free_pages(bio);
bio_put(bio);
return ERR_PTR(-ENOMEM);
}
--
1.9.1
--
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