[PATCH] tmpfs 8/9 misc trivia

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If PAGE_CACHE_SIZE were to differ from PAGE_SIZE, the VM_ACCT macro,
and shmem_nopage's vm_pgoff manipulation, were still not quite right.

Slip a cond_resched_lock into shmem_truncate's long loop; but not into
shmem_unuse_inode's, since other locks held, and swapoff awful anyway.

Move SetPageUptodate to where it's not already set. Replace
copy_from_user by __copy_from_user since access already verified.

Replace BUG()s by BUG_ON()s. Remove an uninteresting PAGE_BUG().

--- tmpfs7/mm/shmem.c Tue Oct 1 19:49:24 2002
+++ tmpfs8/mm/shmem.c Tue Oct 1 19:49:29 2002
@@ -43,7 +43,7 @@
 #define SHMEM_MAX_INDEX (SHMEM_NR_DIRECT + (ENTRIES_PER_PAGEPAGE/2) * (ENTRIES_PER_PAGE+1))
 #define SHMEM_MAX_BYTES ((unsigned long long)SHMEM_MAX_INDEX << PAGE_CACHE_SHIFT)
 
-#define VM_ACCT(size) (((size) + PAGE_CACHE_SIZE - 1) >> PAGE_SHIFT)
+#define VM_ACCT(size) (PAGE_CACHE_ALIGN(size) >> PAGE_SHIFT)
 
 /* Pretend that each entry is of this size in directory's i_size */
 #define BOGO_DIRENT_SIZE 20
@@ -428,6 +428,7 @@
                                 info->alloced++;
                         }
                         empty = subdir;
+ cond_resched_lock(&info->lock);
                         dir = shmem_dir_map(subdir);
                 }
                 subdir = *dir;
@@ -657,10 +658,8 @@
         unsigned long index;
         struct inode *inode;
 
- if (!PageLocked(page))
- BUG();
- if (page_mapped(page))
- BUG();
+ BUG_ON(!PageLocked(page));
+ BUG_ON(page_mapped(page));
 
         mapping = page->mapping;
         index = page->index;
@@ -675,10 +674,8 @@
         spin_lock(&info->lock);
         shmem_recalc_inode(inode);
         entry = shmem_swp_entry(info, index, NULL);
- if (!entry)
- BUG();
- if (entry->val)
- BUG();
+ BUG_ON(!entry);
+ BUG_ON(entry->val);
 
         if (move_to_swap_cache(page, swap) == 0) {
                 shmem_swp_set(info, entry, swap.val);
@@ -852,10 +849,10 @@
                 info->alloced++;
                 spin_unlock(&info->lock);
                 clear_highpage(page);
+ SetPageUptodate(page);
         }
 
         /* We have the page */
- SetPageUptodate(page);
         *pagep = page;
         return 0;
 }
@@ -896,8 +893,9 @@
         unsigned long idx;
         int error;
 
- idx = (address - vma->vm_start) >> PAGE_CACHE_SHIFT;
+ idx = (address - vma->vm_start) >> PAGE_SHIFT;
         idx += vma->vm_pgoff;
+ idx >>= PAGE_CACHE_SHIFT - PAGE_SHIFT;
 
         if (((loff_t) idx << PAGE_CACHE_SHIFT) >= inode->i_size)
                 return NOPAGE_SIGBUS;
@@ -1118,13 +1116,8 @@
                 if (status)
                         break;
 
- /* We have exclusive IO access to the page.. */
- if (!PageLocked(page)) {
- PAGE_BUG(page);
- }
-
                 kaddr = kmap(page);
- status = copy_from_user(kaddr+offset, buf, bytes);
+ status = __copy_from_user(kaddr+offset, buf, bytes);
                 kunmap(page);
                 if (status)
                         goto fail_write;

-
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• Next message: Hugh Dickins: "[PATCH] tmpfs 9/9 whitespace only"
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