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Date: Thu, 18 Jan 2007 15:27:25 -0600
From: Michael Halcrow <mhalcrow@...ibm.com>
To: Andrew Morton <akpm@...l.org>
Cc: linux-kernel@...r.kernel.org
Subject: [PATCH 2/5] eCryptfs: convert kmap() to kmap_atomic()
On Tue, Jan 09, 2007 at 02:42:03PM -0800, Andrew Morton wrote:
> On Tue, 9 Jan 2007 16:23:37 -0600
> Michael Halcrow <mhalcrow@...ibm.com> wrote:
>
> > + page_virt = (char *)kmap(page);
>
> Do we _have_ to use kmap here? It's slow and theoretically
> deadlocky. kmap_atomic() is much preferred.
>
> Can the other kmap() calls in ecryptfs be converted?
Replace kmap() with kmap_atomic(). Reduce the number of kmaps and the
amount of time that kmaps are held.
Signed-off-by: Michael Halcrow <mhalcrow@...ibm.com>
Signed-off-by: Trevor Highland <tshighla@...ibm.com>
---
fs/ecryptfs/crypto.c | 8 +--
fs/ecryptfs/ecryptfs_kernel.h | 4 -
fs/ecryptfs/mmap.c | 121 ++++++++++++-----------------------------
3 files changed, 39 insertions(+), 94 deletions(-)
fd04da707b2164272acc05a56ff4b71786aad011
diff --git a/fs/ecryptfs/crypto.c b/fs/ecryptfs/crypto.c
index fbb62c8..ac4ea8d 100644
--- a/fs/ecryptfs/crypto.c
+++ b/fs/ecryptfs/crypto.c
@@ -429,10 +429,10 @@ static int ecryptfs_read_in_page(struct
goto out;
}
} else {
- rc = ecryptfs_grab_and_map_lower_page(lower_page, NULL,
- lower_inode,
- lower_page_idx);
- if (rc) {
+ *lower_page = grab_cache_page(lower_inode->i_mapping,
+ lower_page_idx);
+ if (!(*lower_page)) {
+ rc = -EINVAL;
ecryptfs_printk(
KERN_ERR, "Error attempting to grab and map "
"lower page with index [0x%.16x]; rc = [%d]\n",
diff --git a/fs/ecryptfs/ecryptfs_kernel.h b/fs/ecryptfs/ecryptfs_kernel.h
index 859d31b..0e38d0d 100644
--- a/fs/ecryptfs/ecryptfs_kernel.h
+++ b/fs/ecryptfs/ecryptfs_kernel.h
@@ -527,10 +527,6 @@ int ecryptfs_copy_page_to_lower(struct p
struct file *lower_file);
int ecryptfs_do_readpage(struct file *file, struct page *page,
pgoff_t lower_page_index);
-int ecryptfs_grab_and_map_lower_page(struct page **lower_page,
- char **lower_virt,
- struct inode *lower_inode,
- unsigned long lower_page_index);
int ecryptfs_writepage_and_release_lower_page(struct page *lower_page,
struct inode *lower_inode,
struct writeback_control *wbc);
diff --git a/fs/ecryptfs/mmap.c b/fs/ecryptfs/mmap.c
index 94bcabf..6f167f1 100644
--- a/fs/ecryptfs/mmap.c
+++ b/fs/ecryptfs/mmap.c
@@ -234,22 +234,11 @@ int ecryptfs_do_readpage(struct file *fi
goto out;
}
wait_on_page_locked(lower_page);
- page_data = (char *)kmap(page);
- if (!page_data) {
- rc = -ENOMEM;
- ecryptfs_printk(KERN_ERR, "Error mapping page\n");
- goto out;
- }
- lower_page_data = (char *)kmap(lower_page);
- if (!lower_page_data) {
- rc = -ENOMEM;
- ecryptfs_printk(KERN_ERR, "Error mapping page\n");
- kunmap(page);
- goto out;
- }
+ page_data = (char *)kmap_atomic(page, KM_USER0);
+ lower_page_data = (char *)kmap_atomic(lower_page, KM_USER1);
memcpy(page_data, lower_page_data, PAGE_CACHE_SIZE);
- kunmap(lower_page);
- kunmap(page);
+ kunmap_atomic(lower_page_data, KM_USER1);
+ kunmap_atomic(page_data, KM_USER0);
rc = 0;
out:
if (likely(lower_page))
@@ -325,19 +314,14 @@ static int ecryptfs_readpage(struct file
if (page->index < num_pages_in_header_region) {
char *page_virt;
- page_virt = (char *)kmap(page);
- if (!page_virt) {
- rc = -ENOMEM;
- printk(KERN_ERR "Error mapping page\n");
- goto out;
- }
+ page_virt = (char *)kmap_atomic(page, KM_USER0);
memset(page_virt, 0, PAGE_CACHE_SIZE);
if (page->index == 0) {
rc = ecryptfs_read_xattr_region(
page_virt, file->f_path.dentry);
set_header_info(page_virt, crypt_stat);
}
- kunmap(page);
+ kunmap_atomic(page_virt, KM_USER0);
if (rc) {
printk(KERN_ERR "Error reading xattr "
"region\n");
@@ -387,26 +371,19 @@ static int fill_zeros_to_end_of_page(str
{
struct inode *inode = page->mapping->host;
int end_byte_in_page;
- int rc = 0;
char *page_virt;
- if ((i_size_read(inode) / PAGE_CACHE_SIZE) == page->index) {
- end_byte_in_page = i_size_read(inode) % PAGE_CACHE_SIZE;
- if (to > end_byte_in_page)
- end_byte_in_page = to;
- page_virt = kmap(page);
- if (!page_virt) {
- rc = -ENOMEM;
- ecryptfs_printk(KERN_WARNING,
- "Could not map page\n");
- goto out;
- }
- memset((page_virt + end_byte_in_page), 0,
- (PAGE_CACHE_SIZE - end_byte_in_page));
- kunmap(page);
- }
+ if ((i_size_read(inode) / PAGE_CACHE_SIZE) != page->index)
+ goto out;
+ end_byte_in_page = i_size_read(inode) % PAGE_CACHE_SIZE;
+ if (to > end_byte_in_page)
+ end_byte_in_page = to;
+ page_virt = kmap_atomic(page, KM_USER0);
+ memset((page_virt + end_byte_in_page), 0,
+ (PAGE_CACHE_SIZE - end_byte_in_page));
+ kunmap_atomic(page_virt, KM_USER0);
out:
- return rc;
+ return 0;
}
static int ecryptfs_prepare_write(struct file *file, struct page *page,
@@ -414,7 +391,6 @@ static int ecryptfs_prepare_write(struct
{
int rc = 0;
- kmap(page);
if (from == 0 && to == PAGE_CACHE_SIZE)
goto out; /* If we are writing a full page, it will be
up to date. */
@@ -424,30 +400,6 @@ out:
return rc;
}
-int ecryptfs_grab_and_map_lower_page(struct page **lower_page,
- char **lower_virt,
- struct inode *lower_inode,
- unsigned long lower_page_index)
-{
- int rc = 0;
-
- (*lower_page) = grab_cache_page(lower_inode->i_mapping,
- lower_page_index);
- if (!(*lower_page)) {
- ecryptfs_printk(KERN_ERR, "grab_cache_page for "
- "lower_page_index = [0x%.16x] failed\n",
- lower_page_index);
- rc = -EINVAL;
- goto out;
- }
- if (lower_virt)
- (*lower_virt) = kmap((*lower_page));
- else
- kmap((*lower_page));
-out:
- return rc;
-}
-
int ecryptfs_writepage_and_release_lower_page(struct page *lower_page,
struct inode *lower_inode,
struct writeback_control *wbc)
@@ -466,11 +418,8 @@ out:
return rc;
}
-static void ecryptfs_unmap_and_release_lower_page(struct page *lower_page)
+static void ecryptfs_release_lower_page(struct page *lower_page)
{
- kunmap(lower_page);
- ecryptfs_printk(KERN_DEBUG, "Unlocking lower page with index = "
- "[0x%.16x]\n", lower_page->index);
unlock_page(lower_page);
page_cache_release(lower_page);
}
@@ -492,11 +441,11 @@ static int ecryptfs_write_inode_size_to_
const struct address_space_operations *lower_a_ops;
u64 file_size;
- rc = ecryptfs_grab_and_map_lower_page(&header_page, &header_virt,
- lower_inode, 0);
- if (rc) {
- ecryptfs_printk(KERN_ERR, "grab_cache_page for header page "
- "failed\n");
+ header_page = grab_cache_page(lower_inode->i_mapping, 0);
+ if (!header_page) {
+ ecryptfs_printk(KERN_ERR, "grab_cache_page for "
+ "lower_page_index 0 failed\n");
+ rc = -EINVAL;
goto out;
}
lower_a_ops = lower_inode->i_mapping->a_ops;
@@ -504,12 +453,14 @@ static int ecryptfs_write_inode_size_to_
file_size = (u64)i_size_read(inode);
ecryptfs_printk(KERN_DEBUG, "Writing size: [0x%.16x]\n", file_size);
file_size = cpu_to_be64(file_size);
+ header_virt = kmap_atomic(header_page, KM_USER0);
memcpy(header_virt, &file_size, sizeof(u64));
+ kunmap_atomic(header_virt, KM_USER0);
rc = lower_a_ops->commit_write(lower_file, header_page, 0, 8);
if (rc < 0)
ecryptfs_printk(KERN_ERR, "Error commiting header page "
"write\n");
- ecryptfs_unmap_and_release_lower_page(header_page);
+ ecryptfs_release_lower_page(header_page);
lower_inode->i_mtime = lower_inode->i_ctime = CURRENT_TIME;
mark_inode_dirty_sync(inode);
out:
@@ -597,10 +548,10 @@ int ecryptfs_get_lower_page(struct page
{
int rc = 0;
- rc = ecryptfs_grab_and_map_lower_page(lower_page, NULL, lower_inode,
- lower_page_index);
- if (rc) {
- ecryptfs_printk(KERN_ERR, "Error attempting to grab and map "
+ *lower_page = grab_cache_page(lower_inode->i_mapping, lower_page_index);
+ if (!(*lower_page)) {
+ rc = -EINVAL;
+ ecryptfs_printk(KERN_ERR, "Error attempting to grab "
"lower page with index [0x%.16x]\n",
lower_page_index);
goto out;
@@ -616,7 +567,7 @@ int ecryptfs_get_lower_page(struct page
}
out:
if (rc && (*lower_page)) {
- ecryptfs_unmap_and_release_lower_page(*lower_page);
+ ecryptfs_release_lower_page(*lower_page);
(*lower_page) = NULL;
}
return rc;
@@ -641,7 +592,7 @@ ecryptfs_commit_lower_page(struct page *
"Error committing write; rc = [%d]\n", rc);
} else
rc = 0;
- ecryptfs_unmap_and_release_lower_page(lower_page);
+ ecryptfs_release_lower_page(lower_page);
return rc;
}
@@ -747,7 +698,6 @@ static int ecryptfs_commit_write(struct
lower_inode->i_mtime = lower_inode->i_ctime = CURRENT_TIME;
mark_inode_dirty_sync(inode);
out:
- kunmap(page); /* mapped in prior call (prepare_write) */
if (rc < 0)
ClearPageUptodate(page);
else
@@ -772,6 +722,7 @@ int write_zeros(struct file *file, pgoff
{
int rc = 0;
struct page *tmp_page;
+ char *tmp_page_virt;
tmp_page = ecryptfs_get1page(file, index);
if (IS_ERR(tmp_page)) {
@@ -780,28 +731,26 @@ int write_zeros(struct file *file, pgoff
rc = PTR_ERR(tmp_page);
goto out;
}
- kmap(tmp_page);
rc = ecryptfs_prepare_write(file, tmp_page, start, start + num_zeros);
if (rc) {
ecryptfs_printk(KERN_ERR, "Error preparing to write zero's "
"to remainder of page at index [0x%.16x]\n",
index);
- kunmap(tmp_page);
page_cache_release(tmp_page);
goto out;
}
- memset(((char *)page_address(tmp_page) + start), 0, num_zeros);
+ tmp_page_virt = kmap_atomic(tmp_page, KM_USER0);
+ memset(((char *)tmp_page_virt + start), 0, num_zeros);
+ kunmap_atomic(tmp_page_virt, KM_USER0);
rc = ecryptfs_commit_write(file, tmp_page, start, start + num_zeros);
if (rc < 0) {
ecryptfs_printk(KERN_ERR, "Error attempting to write zero's "
"to remainder of page at index [0x%.16x]\n",
index);
- kunmap(tmp_page);
page_cache_release(tmp_page);
goto out;
}
rc = 0;
- kunmap(tmp_page);
page_cache_release(tmp_page);
out:
return rc;
--
1.3.3
-
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