函数逻辑报告

Linux Kernel

v5.5.9

Brick Technologies Co., Ltd

Source Code:block\bio.c Create Date:2022-07-27 18:30:40
Last Modify:2020-03-17 23:13:58 Copyright©Brick
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函数名称：__bio_iov_iter_get_pages - pin user or kernel pages and add them to a bio*@bio: bio to add pages to*@iter: iov iterator describing the region to be mapped* Pins pages from *iter and appends them to @bio's bvec array. The

函数原型：static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)

返回类型：int

参数：

类型参数名称
struct bio *bio
struct iov_iter *iter
922  nr_pages等于 max bvl_vecs we can hold 减 how many bio_vec's
923  entries_left等于 max bvl_vecs we can hold 减 how many bio_vec's
924  bv等于 the actual vec list 加 how many bio_vec's
925  pages等于bv
926  bool same_page = false
936  BUILD_BUG_ON - break compile if a condition is true(PAGE_PTRS_PER_BVEC < 2)
937  pages加等于entries_left乘PAGE_PTRS_PER_BVEC减1的差
939  size等于iov_iter_get_pages(iter, pages, LONG_MAX, nr_pages, & offset)
940  如果此条件成立可能性小(为编译器优化)(size <= 0)则返回:如果size则size否则负EFAULT
943  以left大于0循环
944  page等于pages[i]
946  len等于min_t - return minimum of two values, using the specified type*@type: data type to use*@x: first value*@y: second value(size_t, PAGE_SIZE - offset, left)
948  如果__bio_try_merge_page - try appending data to an existing bvec.*@bio: destination bio*@page: start page to add*@len: length of the data to add*@off: offset of the data relative to @page*@same_page: return if the segment has been merged inside the same page则
949  如果same_page则Perform a free_page(), also freeing any swap cache associated with* this page if it is the last user of the page.
951  否则
952  如果WARN_ON_ONCE(_full - check if the bio is full*@bio: bio to check*@len: length of one segment to be added* Return true if @bio is full and one segment with @len bytes can't be* added to the bio, otherwise return false)则返回:负EINVAL
954  __bio_add_page - add page(s) to a bio in a new segment*@bio: destination bio*@page: start page to add*@len: length of the data to add, may cross pages*@off: offset of the data relative to @page, may cross pages
956  offset等于0
959  iov_iter_advance(iter, size)
960  返回:0
调用者
名称描述
bio_iov_iter_get_pages_iov_iter_get_pages - add user or kernel pages to a bio*@bio: bio to add pages to*@iter: iov iterator describing the region to be added* This takes either an iterator pointing to user memory, or one pointing to* kernel pages (BVEC iterator)