linux-2.6.33/generic_perform_write()
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開始行:
*参照元 [#w41e2dfa]
#backlinks
*説明 [#kbdd5d99]
-パス: [[linux-2.6.33/mm/filemap.c]]
-FIXME: これは何？
--説明
**引数 [#o17668cd]
-struct file *file
--
--[[linux-2.6.33/file]]
-struct iov_iter *i
--
--[[linux-2.6.33/iov_iter]]
-loff_t pos
--
**返り値 [#oe377604]
-ssize_t
--
**参考 [#y8df98d1]
*実装 [#j4d217bb]
static ssize_t generic_perform_write(struct file *file,
struct iov_iter *i, loff_t pos)
{
struct address_space *mapping = file->f_mapping;
const struct address_space_operations *a_ops = mapping-...
long status = 0;
ssize_t written = 0;
unsigned int flags = 0;
-
--[[linux-2.6.33/address_space]]
-
--[[linux-2.6.33/address_space_operations]]
/*
* Copies from kernel address space cannot fail (NFSD i...
*/
if (segment_eq(get_fs(), KERNEL_DS))
flags |= AOP_FLAG_UNINTERRUPTIBLE;
-
--[[linux-2.6.33/KERNEL_DS]]
-
--[[linux-2.6.33/AOP_FLAG_UNINTERRUPTIBLE]]
-
--[[linux-2.6.33/segment_eq()]]
-
--[[linux-2.6.33/get_fs()]]
do {
struct page *page;
pgoff_t index; /* Pagecache index for current page */
unsigned long offset; /* Offset into pagecache page */
unsigned long bytes; /* Bytes to write to page */
size_t copied; /* Bytes copied from user */
void *fsdata;
-
--[[linux-2.6.33/page]]
-
--[[linux-2.6.33/pgoff_t]]
offset = (pos & (PAGE_CACHE_SIZE - 1));
index = pos >> PAGE_CACHE_SHIFT;
bytes = min_t(unsigned long, PAGE_CACHE_SIZE - offset,
iov_iter_count(i));
-
--[[linux-2.6.33/PAGE_CACHE_SIZE]]
-
--[[linux-2.6.33/PAGE_CACHE_SHIFT]]
-
--[[linux-2.6.33/min_t()]]
-
--[[linux-2.6.33/iov_iter_count()]]
again:
/*
* Bring in the user page that we will copy from _firs...
* Otherwise there's a nasty deadlock on copying from ...
* same page as we're writing to, without it being mar...
* up-to-date.
*
* Not only is this an optimisation, but it is also re...
* to check that the address is actually valid, when a...
* usercopies are used, below.
*/
if (unlikely(iov_iter_fault_in_readable(i, bytes))) {
status = -EFAULT;
break;
}
-
--[[linux-2.6.33/unlikely()]]
-
--[[linux-2.6.33/iov_iter_fault_in_readable()]]
status = a_ops->write_begin(file, mapping, pos, bytes,...
&page, &fsdata);
if (unlikely(status))
break;
if (mapping_writably_mapped(mapping))
flush_dcache_page(page);
-
--[[linux-2.6.33/mapping_writably_mapped()]]
-
--[[linux-2.6.33/flush_dcache_page()]]
pagefault_disable();
copied = iov_iter_copy_from_user_atomic(page, i, offse...
pagefault_enable();
flush_dcache_page(page);
-
--[[linux-2.6.33/pagefault_disable()]]
-
--[[linux-2.6.33/iov_iter_copy_from_user_atomic()]]
-
--[[linux-2.6.33/pagefault_enable()]]
mark_page_accessed(page);
status = a_ops->write_end(file, mapping, pos, bytes, c...
page, fsdata);
if (unlikely(status < 0))
break;
copied = status;
-
--[[linux-2.6.33/mark_page_accessed()]]
cond_resched();
-
--[[linux-2.6.33/cond_resched()]]
iov_iter_advance(i, copied);
if (unlikely(copied == 0)) {
/*
* If we were unable to copy any data at all, we must
* fall back to a single segment length write.
*
* If we didn't fallback here, we could livelock
* because not all segments in the iov can be copied at
* once without a pagefault.
*/
bytes = min_t(unsigned long, PAGE_CACHE_SIZE - offset,
iov_iter_single_seg_count(i));
goto again;
}
pos += copied;
written += copied;
-
--[[linux-2.6.33/iov_iter_advance()]]
-
--[[linux-2.6.33/iov_iter_single_seg_count()]]
balance_dirty_pages_ratelimited(mapping);
-
--[[linux-2.6.33/balance_dirty_pages_ratelimited()]]
} while (iov_iter_count(i));
-
--[[linux-2.6.33/iov_iter_count()]]
return written ? written : status;
}
*コメント [#k85bc781]
終了行:
*参照元 [#w41e2dfa]
#backlinks
*説明 [#kbdd5d99]
-パス: [[linux-2.6.33/mm/filemap.c]]
-FIXME: これは何？
--説明
**引数 [#o17668cd]
-struct file *file
--
--[[linux-2.6.33/file]]
-struct iov_iter *i
--
--[[linux-2.6.33/iov_iter]]
-loff_t pos
--
**返り値 [#oe377604]
-ssize_t
--
**参考 [#y8df98d1]
*実装 [#j4d217bb]
static ssize_t generic_perform_write(struct file *file,
struct iov_iter *i, loff_t pos)
{
struct address_space *mapping = file->f_mapping;
const struct address_space_operations *a_ops = mapping-...
long status = 0;
ssize_t written = 0;
unsigned int flags = 0;
-
--[[linux-2.6.33/address_space]]
-
--[[linux-2.6.33/address_space_operations]]
/*
* Copies from kernel address space cannot fail (NFSD i...
*/
if (segment_eq(get_fs(), KERNEL_DS))
flags |= AOP_FLAG_UNINTERRUPTIBLE;
-
--[[linux-2.6.33/KERNEL_DS]]
-
--[[linux-2.6.33/AOP_FLAG_UNINTERRUPTIBLE]]
-
--[[linux-2.6.33/segment_eq()]]
-
--[[linux-2.6.33/get_fs()]]
do {
struct page *page;
pgoff_t index; /* Pagecache index for current page */
unsigned long offset; /* Offset into pagecache page */
unsigned long bytes; /* Bytes to write to page */
size_t copied; /* Bytes copied from user */
void *fsdata;
-
--[[linux-2.6.33/page]]
-
--[[linux-2.6.33/pgoff_t]]
offset = (pos & (PAGE_CACHE_SIZE - 1));
index = pos >> PAGE_CACHE_SHIFT;
bytes = min_t(unsigned long, PAGE_CACHE_SIZE - offset,
iov_iter_count(i));
-
--[[linux-2.6.33/PAGE_CACHE_SIZE]]
-
--[[linux-2.6.33/PAGE_CACHE_SHIFT]]
-
--[[linux-2.6.33/min_t()]]
-
--[[linux-2.6.33/iov_iter_count()]]
again:
/*
* Bring in the user page that we will copy from _firs...
* Otherwise there's a nasty deadlock on copying from ...
* same page as we're writing to, without it being mar...
* up-to-date.
*
* Not only is this an optimisation, but it is also re...
* to check that the address is actually valid, when a...
* usercopies are used, below.
*/
if (unlikely(iov_iter_fault_in_readable(i, bytes))) {
status = -EFAULT;
break;
}
-
--[[linux-2.6.33/unlikely()]]
-
--[[linux-2.6.33/iov_iter_fault_in_readable()]]
status = a_ops->write_begin(file, mapping, pos, bytes,...
&page, &fsdata);
if (unlikely(status))
break;
if (mapping_writably_mapped(mapping))
flush_dcache_page(page);
-
--[[linux-2.6.33/mapping_writably_mapped()]]
-
--[[linux-2.6.33/flush_dcache_page()]]
pagefault_disable();
copied = iov_iter_copy_from_user_atomic(page, i, offse...
pagefault_enable();
flush_dcache_page(page);
-
--[[linux-2.6.33/pagefault_disable()]]
-
--[[linux-2.6.33/iov_iter_copy_from_user_atomic()]]
-
--[[linux-2.6.33/pagefault_enable()]]
mark_page_accessed(page);
status = a_ops->write_end(file, mapping, pos, bytes, c...
page, fsdata);
if (unlikely(status < 0))
break;
copied = status;
-
--[[linux-2.6.33/mark_page_accessed()]]
cond_resched();
-
--[[linux-2.6.33/cond_resched()]]
iov_iter_advance(i, copied);
if (unlikely(copied == 0)) {
/*
* If we were unable to copy any data at all, we must
* fall back to a single segment length write.
*
* If we didn't fallback here, we could livelock
* because not all segments in the iov can be copied at
* once without a pagefault.
*/
bytes = min_t(unsigned long, PAGE_CACHE_SIZE - offset,
iov_iter_single_seg_count(i));
goto again;
}
pos += copied;
written += copied;
-
--[[linux-2.6.33/iov_iter_advance()]]
-
--[[linux-2.6.33/iov_iter_single_seg_count()]]
balance_dirty_pages_ratelimited(mapping);
-
--[[linux-2.6.33/balance_dirty_pages_ratelimited()]]
} while (iov_iter_count(i));
-
--[[linux-2.6.33/iov_iter_count()]]
return written ? written : status;
}
*コメント [#k85bc781]
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