d9d90e5eb7
Although it is used (by i915) on nothing but tmpfs, read_cache_page_gfp() is unsuited to tmpfs, because it inserts a page into pagecache before calling the filesystem's ->readpage: tmpfs may have pages in swapcache which only it knows how to locate and switch to filecache. At present tmpfs provides a ->readpage method, and copes with this by copying pages; but soon we can simplify it by removing its ->readpage. Provide shmem_read_mapping_page_gfp() now, ready for that transition, Export shmem_read_mapping_page_gfp() and add it to list in shmem_fs.h, with shmem_read_mapping_page() inline for the common mapping_gfp case. (shmem_read_mapping_page_gfp or shmem_read_cache_page_gfp? Generally the read_mapping_page functions use the mapping's ->readpage, and the read_cache_page functions use the supplied filler, so I think read_cache_page_gfp was slightly misnamed.) Signed-off-by: Hugh Dickins <hughd@google.com> Cc: Christoph Hellwig <hch@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
73 lines
2.6 KiB
C
73 lines
2.6 KiB
C
#ifndef __SHMEM_FS_H
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#define __SHMEM_FS_H
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#include <linux/swap.h>
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#include <linux/mempolicy.h>
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#include <linux/pagemap.h>
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#include <linux/percpu_counter.h>
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/* inode in-kernel data */
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#define SHMEM_NR_DIRECT 16
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#define SHMEM_SYMLINK_INLINE_LEN (SHMEM_NR_DIRECT * sizeof(swp_entry_t))
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struct shmem_inode_info {
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spinlock_t lock;
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unsigned long flags;
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unsigned long alloced; /* data pages alloced to file */
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unsigned long swapped; /* subtotal assigned to swap */
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unsigned long next_index; /* highest alloced index + 1 */
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struct shared_policy policy; /* NUMA memory alloc policy */
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struct page *i_indirect; /* top indirect blocks page */
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union {
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swp_entry_t i_direct[SHMEM_NR_DIRECT]; /* first blocks */
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char inline_symlink[SHMEM_SYMLINK_INLINE_LEN];
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};
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struct list_head swaplist; /* chain of maybes on swap */
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struct list_head xattr_list; /* list of shmem_xattr */
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struct inode vfs_inode;
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};
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struct shmem_sb_info {
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unsigned long max_blocks; /* How many blocks are allowed */
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struct percpu_counter used_blocks; /* How many are allocated */
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unsigned long max_inodes; /* How many inodes are allowed */
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unsigned long free_inodes; /* How many are left for allocation */
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spinlock_t stat_lock; /* Serialize shmem_sb_info changes */
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uid_t uid; /* Mount uid for root directory */
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gid_t gid; /* Mount gid for root directory */
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mode_t mode; /* Mount mode for root directory */
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struct mempolicy *mpol; /* default memory policy for mappings */
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};
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static inline struct shmem_inode_info *SHMEM_I(struct inode *inode)
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{
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return container_of(inode, struct shmem_inode_info, vfs_inode);
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}
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/*
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* Functions in mm/shmem.c called directly from elsewhere:
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*/
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extern int init_tmpfs(void);
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extern int shmem_fill_super(struct super_block *sb, void *data, int silent);
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extern struct file *shmem_file_setup(const char *name,
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loff_t size, unsigned long flags);
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extern int shmem_zero_setup(struct vm_area_struct *);
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extern int shmem_lock(struct file *file, int lock, struct user_struct *user);
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extern struct page *shmem_read_mapping_page_gfp(struct address_space *mapping,
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pgoff_t index, gfp_t gfp_mask);
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extern void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end);
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extern int shmem_unuse(swp_entry_t entry, struct page *page);
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extern void mem_cgroup_get_shmem_target(struct inode *inode, pgoff_t pgoff,
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struct page **pagep, swp_entry_t *ent);
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static inline struct page *shmem_read_mapping_page(
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struct address_space *mapping, pgoff_t index)
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{
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return shmem_read_mapping_page_gfp(mapping, index,
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mapping_gfp_mask(mapping));
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}
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#endif
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