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read_cache_pages() also working copied from write_cache_pages()

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- Need to remove old versions
- Need to merge the two.
- Need to investigate occasional page fault on NMOP sequence. (resembles an error ipc_extended test)
  Could be related to new page cache read/write routines.
This commit is contained in:
Bahadir Balban
2009-10-14 01:48:05 +03:00
parent ee2bf8e7f3
commit 3a3204986e
5 changed files with 92 additions and 24 deletions
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94
conts/posix/mm0/mm/file.c
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@@ -510,6 +510,67 @@ int new_file_pages(struct vm_file *f, unsigned long start, unsigned long end)
#define page_offset(x) ((unsigned long)(x) & PAGE_MASK)
/*
* Writes user data in buffer into pages in cache. If a page is not
* found, it's a bug. The writeable page range must have been readied
* by read_file_pages()/new_file_pages().
*/
int read_cache_pages(struct vm_file *vmfile, struct tcb *task, void *buf,
unsigned long pfn_start, unsigned long pfn_end,
unsigned long cursor_offset, int count)
{
struct page *file_page;
unsigned long task_offset; /* Current copy offset on the task buffer */
unsigned long file_offset; /* Current copy offset on the file */
int copysize, left;
int empty;
task_offset = (unsigned long)buf;
file_offset = cursor_offset;
left = count;
/* Find the head of consecutive pages */
list_foreach_struct(file_page, &vmfile->vm_obj.page_cache, list) {
if (file_page->offset < pfn_start)
continue;
else if (file_page->offset == pfn_end || left == 0)
break;
empty = PAGE_SIZE - page_offset(file_offset);
/* Copy until a single page cache page is filled */
while (empty && left) {
copysize = min(PAGE_SIZE - page_offset(file_offset), left);
copysize = min(copysize, PAGE_SIZE - page_offset(task_offset));
/*
printf("empty: %d, left: %d, copysize: "
"%d, copy to page with pfn %lx, "
"offset 0x%lx, from page with pfn "
"%lx, offset 0x%lx\n", empty, left,
copysize,
task_virt_to_page(task,task_offset)->offset,
page_offset(task_offset),
file_page->offset,
page_offset(file_offset));
*/
page_copy(task_virt_to_page(task, task_offset),
file_page,
page_offset(task_offset),
page_offset(file_offset),
copysize);
empty -= copysize;
left -= copysize;
task_offset += copysize;
file_offset += copysize;
}
}
BUG_ON(left != 0);
return count - left;
}
/*
* Writes user data in buffer into pages in cache. If a page is not
* found, it's a bug. The writeable page range must have been readied
@@ -529,9 +590,6 @@ int write_cache_pages(struct vm_file *vmfile, struct tcb *task, void *buf,
file_offset = cursor_offset;
left = count;
printf("%s: cursor_offset: 0x%lx, count: 0x%x, buf: %p\n",
__FUNCTION__, cursor_offset, count, buf);
/* Find the head of consecutive pages */
list_foreach_struct(file_page, &vmfile->vm_obj.page_cache, list) {
if (file_page->offset < pfn_start)
@@ -541,15 +599,26 @@ int write_cache_pages(struct vm_file *vmfile, struct tcb *task, void *buf,
empty = PAGE_SIZE - page_offset(file_offset);
/* Copy until the page is filled */
/* Copy until a single page cache page is filled */
while (empty && left) {
copysize = min(PAGE_SIZE - page_offset(file_offset), left);
copysize = min(copysize, PAGE_SIZE - page_offset(task_offset));
//printf("empty: %d, left: %d, copysize: %d, copy to page with pfn %lx, offset 0x%lx, from page with pfn %lx, offset 0x%lx\n",
// empty, left, copysize, file_page->offset, page_offset(file_offset),task_virt_to_page(task,task_offset)->offset, page_offset(task_offset));
page_copy(file_page, task_virt_to_page(task, task_offset),
page_offset(file_offset), page_offset(task_offset),
/*
printf("empty: %d, left: %d, copysize: "
"%d, copy to page with pfn %lx, "
"offset 0x%lx, from page with pfn "
"%lx, offset 0x%lx\n", empty, left,
copysize, file_page->offset,
page_offset(file_offset),
task_virt_to_page(task,task_offset)->offset,
page_offset(task_offset));
*/
page_copy(file_page,
task_virt_to_page(task, task_offset),
page_offset(file_offset),
page_offset(task_offset),
copysize);
empty -= copysize;
left -= copysize;
task_offset += copysize;
@@ -572,7 +641,7 @@ int write_cache_pages(struct vm_file *vmfile, struct tcb *task, void *buf,
* be called first and count must be checked. Since it has read-checking
* assumptions, count must be satisfied.
*/
int read_cache_pages(struct vm_file *vmfile, struct tcb *task, void *buf,
int read_cache_pages_orig(struct vm_file *vmfile, struct tcb *task, void *buf,
unsigned long pfn_start, unsigned long pfn_end,
unsigned long cursor_offset, int count)
{
@@ -630,7 +699,7 @@ copy:
int sys_read(struct tcb *task, int fd, void *buf, int count)
{
unsigned long pfn_start, pfn_end;
unsigned long cursor, byte_offset;
unsigned long cursor;
struct vm_file *vmfile;
int ret = 0;
@@ -675,12 +744,9 @@ int sys_read(struct tcb *task, int fd, void *buf, int count)
if ((ret = read_file_pages(vmfile, pfn_start, pfn_end)) < 0)
return ret;
/* The offset of cursor on first page */
byte_offset = PAGE_MASK & cursor;
/* Read it into the user buffer from the cache */
if ((count = read_cache_pages(vmfile, task, buf, pfn_start, pfn_end,
byte_offset, count)) < 0)
cursor, count)) < 0)
return count;
/* Update cursor on success */