forked from luck/tmp_suning_uos_patched
eb6fe0c388
This patch reworks filemap_xip.c with the goal to reduce code duplication from mm/filemap.c. It applies agains 2.6.12-rc6-mm1. Instead of implementing the aio functions, this one implements the synchronous read/write functions only. For readv and writev, the generic fallback is used. For aio, we rely on the application doing the fallback. Since our "synchronous" function does memcpy immediately anyway, there is no performance difference between using the fallbacks or implementing each operation. Signed-off-by: Carsten Otte <cotte@de.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
95 lines
2.2 KiB
C
95 lines
2.2 KiB
C
/*
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* linux/mm/filemap.h
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*
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* Copyright (C) 1994-1999 Linus Torvalds
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*/
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#ifndef __FILEMAP_H
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#define __FILEMAP_H
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#include <linux/types.h>
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#include <linux/fs.h>
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#include <linux/mm.h>
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#include <linux/highmem.h>
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#include <linux/uio.h>
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#include <linux/config.h>
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#include <asm/uaccess.h>
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size_t
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__filemap_copy_from_user_iovec(char *vaddr,
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const struct iovec *iov,
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size_t base,
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size_t bytes);
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/*
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* Copy as much as we can into the page and return the number of bytes which
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* were sucessfully copied. If a fault is encountered then clear the page
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* out to (offset+bytes) and return the number of bytes which were copied.
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*/
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static inline size_t
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filemap_copy_from_user(struct page *page, unsigned long offset,
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const char __user *buf, unsigned bytes)
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{
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char *kaddr;
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int left;
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kaddr = kmap_atomic(page, KM_USER0);
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left = __copy_from_user_inatomic(kaddr + offset, buf, bytes);
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kunmap_atomic(kaddr, KM_USER0);
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if (left != 0) {
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/* Do it the slow way */
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kaddr = kmap(page);
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left = __copy_from_user(kaddr + offset, buf, bytes);
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kunmap(page);
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}
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return bytes - left;
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}
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/*
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* This has the same sideeffects and return value as filemap_copy_from_user().
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* The difference is that on a fault we need to memset the remainder of the
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* page (out to offset+bytes), to emulate filemap_copy_from_user()'s
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* single-segment behaviour.
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*/
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static inline size_t
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filemap_copy_from_user_iovec(struct page *page, unsigned long offset,
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const struct iovec *iov, size_t base, size_t bytes)
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{
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char *kaddr;
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size_t copied;
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kaddr = kmap_atomic(page, KM_USER0);
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copied = __filemap_copy_from_user_iovec(kaddr + offset, iov,
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base, bytes);
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kunmap_atomic(kaddr, KM_USER0);
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if (copied != bytes) {
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kaddr = kmap(page);
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copied = __filemap_copy_from_user_iovec(kaddr + offset, iov,
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base, bytes);
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kunmap(page);
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}
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return copied;
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}
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static inline void
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filemap_set_next_iovec(const struct iovec **iovp, size_t *basep, size_t bytes)
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{
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const struct iovec *iov = *iovp;
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size_t base = *basep;
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while (bytes) {
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int copy = min(bytes, iov->iov_len - base);
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bytes -= copy;
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base += copy;
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if (iov->iov_len == base) {
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iov++;
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base = 0;
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}
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}
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*iovp = iov;
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*basep = base;
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}
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#endif
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