/* * Copyright (c) 2000-2002 Silicon Graphics, Inc. All Rights Reserved. * * This program is free software; you can redistribute it and/or modify it * under the terms of version 2 of the GNU General Public License as * published by the Free Software Foundation. * * This program is distributed in the hope that it would be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. * * Further, this software is distributed without any warranty that it is * free of the rightful claim of any third person regarding infringement * or the like. Any license provided herein, whether implied or * otherwise, applies only to this software file. Patent licenses, if * any, provided herein do not apply to combinations of this program with * other software, or any other product whatsoever. * * You should have received a copy of the GNU General Public License along * with this program; if not, write the Free Software Foundation, Inc., 59 * Temple Place - Suite 330, Boston MA 02111-1307, USA. * * Contact information: Silicon Graphics, Inc., 1600 Amphitheatre Pkwy, * Mountain View, CA 94043, or: * * http://www.sgi.com * * For further information regarding this notice, see: * * http://oss.sgi.com/projects/GenInfo/SGIGPLNoticeExplan/ */ /* * Written by Steve Lord, Jim Mostek, Russell Cattelan at SGI */ #ifndef __PAGE_BUF_H__ #define __PAGE_BUF_H__ #include <linux/config.h> #include <linux/list.h> #include <linux/types.h> #include <linux/spinlock.h> #include <asm/system.h> #include <linux/mm.h> #include <linux/fs.h> #include <linux/buffer_head.h> #include <linux/uio.h> /* * Base types */ /* daddr must be signed since -1 is used for bmaps that are not yet allocated */ typedef loff_t page_buf_daddr_t; #define PAGE_BUF_DADDR_NULL ((page_buf_daddr_t) (-1LL)) #define page_buf_ctob(pp) ((pp) * PAGE_CACHE_SIZE) #define page_buf_btoc(dd) (((dd) + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT) #define page_buf_btoct(dd) ((dd) >> PAGE_CACHE_SHIFT) #define page_buf_poff(aa) ((aa) & ~PAGE_CACHE_MASK) typedef enum page_buf_rw_e { PBRW_READ = 1, /* transfer into target memory */ PBRW_WRITE = 2, /* transfer from target memory */ PBRW_ZERO = 3 /* Zero target memory */ } page_buf_rw_t; typedef enum page_buf_flags_e { /* pb_flags values */ PBF_READ = (1 << 0), /* buffer intended for reading from device */ PBF_WRITE = (1 << 1), /* buffer intended for writing to device */ PBF_MAPPED = (1 << 2), /* buffer mapped (pb_addr valid) */ PBF_PARTIAL = (1 << 3), /* buffer partially read */ PBF_ASYNC = (1 << 4), /* initiator will not wait for completion */ PBF_NONE = (1 << 5), /* buffer not read at all */ PBF_DELWRI = (1 << 6), /* buffer has dirty pages */ PBF_FREED = (1 << 7), /* buffer has been freed and is invalid */ PBF_SYNC = (1 << 8), /* force updates to disk */ PBF_MAPPABLE = (1 << 9),/* use directly-addressable pages */ PBF_STALE = (1 << 10), /* buffer has been staled, do not find it */ PBF_FS_MANAGED = (1 << 11), /* filesystem controls freeing memory */ PBF_FS_DATAIOD = (1 << 12), /* schedule IO completion on fs datad */ /* flags used only as arguments to access routines */ PBF_LOCK = (1 << 13), /* lock requested */ PBF_TRYLOCK = (1 << 14), /* lock requested, but do not wait */ PBF_DONT_BLOCK = (1 << 15), /* do not block in current thread */ /* flags used only internally */ _PBF_LOCKABLE = (1 << 16), /* page_buf_t may be locked */ _PBF_PRIVATE_BH = (1 << 17), /* do not use public buffer heads */ _PBF_ALL_PAGES_MAPPED = (1 << 18), /* all pages in range mapped */ _PBF_ADDR_ALLOCATED = (1 << 19), /* pb_addr space was allocated */ _PBF_MEM_ALLOCATED = (1 << 20), /* underlying pages are allocated */ _PBF_MEM_SLAB = (1 << 21), /* underlying pages are slab allocated */ PBF_FORCEIO = (1 << 22), /* ignore any cache state */ PBF_FLUSH = (1 << 23), /* flush disk write cache */ PBF_READ_AHEAD = (1 << 24), /* asynchronous read-ahead */ PBF_RUN_QUEUES = (1 << 25), /* run block device task queue */ } page_buf_flags_t; #define PBF_UPDATE (PBF_READ | PBF_WRITE) #define PBF_NOT_DONE(pb) (((pb)->pb_flags & (PBF_PARTIAL|PBF_NONE)) != 0) #define PBF_DONE(pb) (((pb)->pb_flags & (PBF_PARTIAL|PBF_NONE)) == 0) typedef struct pb_target { dev_t pbr_dev; struct block_device *pbr_bdev; struct address_space *pbr_mapping; unsigned int pbr_bsize; unsigned int pbr_sshift; size_t pbr_smask; } pb_target_t; /* * page_buf_t: Buffer structure for page cache-based buffers * * This buffer structure is used by the page cache buffer management routines * to refer to an assembly of pages forming a logical buffer. The actual * I/O is performed with buffer_head or bio structures, as required by drivers, * for drivers which do not understand this structure. The buffer structure is * used on temporary basis only, and discarded when released. * * The real data storage is recorded in the page cache. Metadata is * hashed to the inode for the block device on which the file system resides. * File data is hashed to the inode for the file. Pages which are only * partially filled with data have bits set in their block_map entry * to indicate which disk blocks in the page are not valid. */ struct page_buf_s; typedef void (*page_buf_iodone_t)(struct page_buf_s *); /* call-back function on I/O completion */ typedef void (*page_buf_relse_t)(struct page_buf_s *); /* call-back function on I/O completion */ typedef int (*page_buf_bdstrat_t)(struct page_buf_s *); #define PB_PAGES 4 typedef struct page_buf_s { struct semaphore pb_sema; /* semaphore for lockables */ unsigned long pb_flushtime; /* time to flush pagebuf */ atomic_t pb_pin_count; /* pin count */ wait_queue_head_t pb_waiters; /* unpin waiters */ struct list_head pb_list; page_buf_flags_t pb_flags; /* status flags */ struct list_head pb_hash_list; struct pb_target *pb_target; /* logical object */ atomic_t pb_hold; /* reference count */ page_buf_daddr_t pb_bn; /* block number for I/O */ loff_t pb_file_offset; /* offset in file */ size_t pb_buffer_length; /* size of buffer in bytes */ size_t pb_count_desired; /* desired transfer size */ void *pb_addr; /* virtual address of buffer */ struct work_struct pb_iodone_work; atomic_t pb_io_remaining;/* #outstanding I/O requests */ page_buf_iodone_t pb_iodone; /* I/O completion function */ page_buf_relse_t pb_relse; /* releasing function */ page_buf_bdstrat_t pb_strat; /* pre-write function */ struct semaphore pb_iodonesema; /* Semaphore for I/O waiters */ void *pb_fspriv; void *pb_fspriv2; void *pb_fspriv3; unsigned short pb_error; /* error code on I/O */ unsigned short pb_page_count; /* size of page array */ unsigned short pb_offset; /* page offset in first page */ unsigned char pb_locked; /* page array is locked */ unsigned char pb_hash_index; /* hash table index */ struct page **pb_pages; /* array of page pointers */ struct page *pb_page_array[PB_PAGES]; /* inline pages */ #ifdef PAGEBUF_LOCK_TRACKING int pb_last_holder; #endif } page_buf_t; /* Finding and Reading Buffers */ extern page_buf_t *pagebuf_find( /* find buffer for block if */ /* the block is in memory */ struct pb_target *, /* inode for block */ loff_t, /* starting offset of range */ size_t, /* length of range */ page_buf_flags_t); /* PBF_LOCK */ extern page_buf_t *pagebuf_get( /* allocate a buffer */ struct pb_target *, /* inode for buffer */ loff_t, /* starting offset of range */ size_t, /* length of range */ page_buf_flags_t); /* PBF_LOCK, PBF_READ, */ /* PBF_ASYNC */ extern page_buf_t *pagebuf_lookup( struct pb_target *, loff_t, /* starting offset of range */ size_t, /* length of range */ page_buf_flags_t); /* PBF_READ, PBF_WRITE, */ /* PBF_FORCEIO, _PBF_LOCKABLE */ extern page_buf_t *pagebuf_get_empty( /* allocate pagebuf struct with */ /* no memory or disk address */ size_t len, struct pb_target *); /* mount point "fake" inode */ extern page_buf_t *pagebuf_get_no_daddr(/* allocate pagebuf struct */ /* without disk address */ size_t len, struct pb_target *); /* mount point "fake" inode */ extern int pagebuf_associate_memory( page_buf_t *, void *, size_t); extern void pagebuf_hold( /* increment reference count */ page_buf_t *); /* buffer to hold */ extern void pagebuf_readahead( /* read ahead into cache */ struct pb_target *, /* target for buffer (or NULL) */ loff_t, /* starting offset of range */ size_t, /* length of range */ page_buf_flags_t); /* additional read flags */ /* Releasing Buffers */ extern void pagebuf_free( /* deallocate a buffer */ page_buf_t *); /* buffer to deallocate */ extern void pagebuf_rele( /* release hold on a buffer */ page_buf_t *); /* buffer to release */ /* Locking and Unlocking Buffers */ extern int pagebuf_cond_lock( /* lock buffer, if not locked */ /* (returns -EBUSY if locked) */ page_buf_t *); /* buffer to lock */ extern int pagebuf_lock_value( /* return count on lock */ page_buf_t *); /* buffer to check */ extern int pagebuf_lock( /* lock buffer */ page_buf_t *); /* buffer to lock */ extern void pagebuf_unlock( /* unlock buffer */ page_buf_t *); /* buffer to unlock */ /* Buffer Read and Write Routines */ extern void pagebuf_iodone( /* mark buffer I/O complete */ page_buf_t *, /* buffer to mark */ int, /* use data/log helper thread. */ int); /* run completion locally, or in * a helper thread. */ extern void pagebuf_ioerror( /* mark buffer in error (or not) */ page_buf_t *, /* buffer to mark */ unsigned int); /* error to store (0 if none) */ extern int pagebuf_iostart( /* start I/O on a buffer */ page_buf_t *, /* buffer to start */ page_buf_flags_t); /* PBF_LOCK, PBF_ASYNC, */ /* PBF_READ, PBF_WRITE, */ /* PBF_DELWRI, PBF_SYNC */ extern int pagebuf_iorequest( /* start real I/O */ page_buf_t *); /* buffer to convey to device */ extern int pagebuf_iowait( /* wait for buffer I/O done */ page_buf_t *); /* buffer to wait on */ extern void pagebuf_iomove( /* move data in/out of pagebuf */ page_buf_t *, /* buffer to manipulate */ size_t, /* starting buffer offset */ size_t, /* length in buffer */ caddr_t, /* data pointer */ page_buf_rw_t); /* direction */ static inline int pagebuf_iostrategy(page_buf_t *pb) { return pb->pb_strat ? pb->pb_strat(pb) : pagebuf_iorequest(pb); } static inline int pagebuf_geterror(page_buf_t *pb) { return pb ? pb->pb_error : ENOMEM; } /* Buffer Utility Routines */ extern caddr_t pagebuf_offset( /* pointer at offset in buffer */ page_buf_t *, /* buffer to offset into */ size_t); /* offset */ /* Pinning Buffer Storage in Memory */ extern void pagebuf_pin( /* pin buffer in memory */ page_buf_t *); /* buffer to pin */ extern void pagebuf_unpin( /* unpin buffered data */ page_buf_t *); /* buffer to unpin */ extern int pagebuf_ispin( /* check if buffer is pinned */ page_buf_t *); /* buffer to check */ /* Delayed Write Buffer Routines */ #define PBDF_WAIT 0x01 extern void pagebuf_delwri_flush( pb_target_t *, unsigned long, int *); extern void pagebuf_delwri_dequeue( page_buf_t *); /* Buffer Daemon Setup Routines */ extern int pagebuf_init(void); extern void pagebuf_terminate(void); #ifdef PAGEBUF_TRACE extern ktrace_t *pagebuf_trace_buf; extern void pagebuf_trace( page_buf_t *, /* buffer being traced */ char *, /* description of operation */ void *, /* arbitrary diagnostic value */ void *); /* return address */ #else # define pagebuf_trace(pb, id, ptr, ra) do { } while (0) #endif #endif /* __PAGE_BUF_H__ */