+__BEGIN_DECLS
+
+/*!
+ @function buf_markaged
+ @abstract Mark a buffer as "aged," i.e. as a good candidate to be discarded and reused after buf_brelse().
+ @param bp Buffer to mark.
+ */
+void buf_markaged(buf_t);
+
+/*!
+ @function buf_markinvalid
+ @abstract Mark a buffer as not having valid data and being ready for immediate reuse after buf_brelse().
+ @param bp Buffer to mark.
+ */
+void buf_markinvalid(buf_t);
+
+/*!
+ @function buf_markdelayed
+ @abstract Mark a buffer as a delayed write: mark it dirty without actually scheduling I/O.
+ @discussion Data will be flushed to disk at some later time, not with brelse(). A sync()/fsync()
+ or pressure necessitating reuse of the buffer will cause it to be written back to disk.
+ @param bp Buffer to mark.
+ */
+void buf_markdelayed(buf_t);
+
+void buf_markclean(buf_t);
+
+/*!
+ @function buf_markeintr
+ @abstract Mark a buffer as having been interrupted during I/O.
+ @discussion Waiters for I/O to complete (buf_biowait()) will return with EINTR when woken up.
+ buf_markeintr does not itself do a wakeup.
+ @param bp Buffer to mark.
+ */
+void buf_markeintr(buf_t);
+
+/*!
+ @function buf_markfua
+ @abstract Mark a buffer for write through disk cache, if disk supports it.
+ @param bp Buffer to mark.
+ */
+void buf_markfua(buf_t);
+
+/*!
+ @function buf_fua
+ @abstract Check if a buffer is marked for write through disk caches.
+ @param bp Buffer to test.
+ @return Nonzero if buffer is marked for write-through, 0 if not.
+ */
+int buf_fua(buf_t);
+
+/*!
+ @function buf_valid
+ @abstract Check if a buffer contains valid data.
+ @param bp Buffer to test.
+ @return Nonzero if buffer has valid data, 0 if not.
+ */
+int buf_valid(buf_t);
+
+/*!
+ @function buf_fromcache
+ @abstract Check if a buffer's data was found in core.
+ @discussion Will return truth after a buf_getblk that finds a valid buffer in the cache or the relevant
+ data in core (but not in a buffer).
+ @param bp Buffer to test.
+ @return Nonzero if we got this buffer's data without doing I/O, 0 if not.
+ */
+int buf_fromcache(buf_t);
+
+/*!
+ @function buf_upl
+ @abstract Get the upl (Universal Page List) associated with a buffer.
+ @discussion Buffers allocated with buf_alloc() are not returned with a upl, and
+ traditional buffers only have a upl while an I/O is in progress.
+ @param bp Buffer whose upl to grab.
+ @return Buffer's upl if it has one, else NULL.
+ */
+void * buf_upl(buf_t);
+
+/*!
+ @function buf_uploffset
+ @abstract Get the offset into a UPL at which this buffer begins.
+ @discussion This function should only be called on iobufs, i.e. buffers allocated with buf_alloc().
+ @param bp Buffer whose uploffset to grab.
+ @return Buffer's uploffset--does not check whether that value makes sense for this buffer.
+ */
+uint32_t buf_uploffset(buf_t);
+
+/*!
+ @function buf_rcred
+ @abstract Get the credential associated with a buffer for reading.
+ @discussion No reference is taken; if the credential is to be held on to persistently, an additional
+ reference must be taken with kauth_cred_ref.
+ @param bp Buffer whose credential to grab.
+ @return Credential if it exists, else NULL.
+ */
+kauth_cred_t buf_rcred(buf_t);
+
+/*!
+ @function buf_wcred
+ @abstract Get the credential associated with a buffer for writing.
+ @discussion No reference is taken; if the credential is to be held on to persistently, an additional
+ reference must be taken with kauth_cred_ref.
+ @param bp Buffer whose credential to grab.
+ @return Credential if it exists, else NULL.
+ */
+kauth_cred_t buf_wcred(buf_t);
+
+/*!
+ @function buf_proc
+ @abstract Get the process associated with this buffer.
+ @discussion buf_proc() will generally return NULL; a process is currently only associated with
+ a buffer in the event of a physio() call.
+ @param bp Buffer whose associated process to find.
+ @return Associated process, possibly NULL.
+ */
+proc_t buf_proc(buf_t);
+
+/*!
+ @function buf_dirtyoff
+ @abstract Get the starting offset of the dirty region associated with a buffer.
+ @discussion The dirty offset is zero unless someone explicitly calls buf_setdirtyoff() (which the kernel does not).
+ @param bp Buffer whose dirty offset to get.
+ @return Dirty offset (0 if not explicitly changed).
+ */
+uint32_t buf_dirtyoff(buf_t);
+
+/*!
+ @function buf_dirtyend
+ @abstract Get the ending offset of the dirty region associated with a buffer.
+ @discussion If the buffer's data was found incore and dirty, the dirty end is the size of the block; otherwise, unless
+ someone outside of xnu explicitly changes it by calling buf_setdirtyend(), it will be zero.
+ @param bp Buffer whose dirty end to get.
+ @return 0 if buffer is found clean; size of buffer if found dirty. Can be set to any value by callers of buf_setdirtyend().
+ */
+uint32_t buf_dirtyend(buf_t);
+
+/*!
+ @function buf_setdirtyoff
+ @abstract Set the starting offset of the dirty region associated with a buffer.
+ @discussion This value is zero unless someone set it explicitly.
+ @param bp Buffer whose dirty end to set.
+ @return void.
+ */
+void buf_setdirtyoff(buf_t, uint32_t);
+
+/*!
+ @function buf_setdirtyend
+ @abstract Set the ending offset of the dirty region associated with a buffer.
+ @discussion If the buffer's data was found incore and dirty, the dirty end is the size of the block; otherwise, unless
+ someone outside of xnu explicitly changes it by calling buf_setdirtyend(), it will be zero.
+ @param bp Buffer whose dirty end to set.
+ @return void.
+ */
+void buf_setdirtyend(buf_t, uint32_t);
+
+/*!
+ @function buf_error
+ @abstract Get the error value associated with a buffer.
+ @discussion Errors are set with buf_seterror().
+ @param bp Buffer whose error value to retrieve.
+ @return Error value, directly.
+ */
+errno_t buf_error(buf_t);
+
+/*!
+ @function buf_seterror
+ @abstract Set an error value on a buffer.
+ @param bp Buffer whose error value to set.
+ @return void.
+ */
+void buf_seterror(buf_t, errno_t);
+
+/*!
+ @function buf_setflags
+ @abstract Set flags on a buffer.
+ @discussion: buffer_flags |= flags
+ @param bp Buffer whose flags to set.
+ @param flags Flags to add to buffer's mask. B_LOCKED/B_NOCACHE/B_ASYNC/B_READ/B_WRITE/B_PAGEIO/B_FUA
+ @return void.
+ */
+void buf_setflags(buf_t, int32_t);
+
+/*!
+ @function buf_clearflags
+ @abstract Clear flags on a buffer.
+ @discussion: buffer_flags &= ~flags
+ @param bp Buffer whose flags to clear.
+ @param flags Flags to remove from buffer's mask. B_LOCKED/B_NOCACHE/B_ASYNC/B_READ/B_WRITE/B_PAGEIO/B_FUA
+ @return void.
+ */
+void buf_clearflags(buf_t, int32_t);
+
+/*!
+ @function buf_flags
+ @abstract Get flags set on a buffer.
+ @discussion Valid flags are B_LOCKED/B_NOCACHE/B_ASYNC/B_READ/B_WRITE/B_PAGEIO/B_FUA.
+ @param bp Buffer whose flags to grab.
+ @return flags.
+ */
+int32_t buf_flags(buf_t);
+
+/*!
+ @function buf_reset
+ @abstract Reset I/O flag state on a buffer.
+ @discussion Clears current flags on a buffer (internal and external) and allows some new flags to be set.
+ Used perhaps to prepare an iobuf for reuse.
+ @param bp Buffer whose flags to grab.
+ @param flags Flags to set on buffer: B_READ, B_WRITE, B_ASYNC, B_NOCACHE.
+ @return void.
+ */
+void buf_reset(buf_t, int32_t);
+
+/*!
+ @function buf_map
+ @abstract Get virtual mappings for buffer data.
+ @discussion For buffers created through buf_getblk() (i.e. traditional buffer cache usage),
+ buf_map() just returns the address at which data was mapped by but_getblk(). For a B_CLUSTER buffer, i.e. an iobuf
+ whose upl state is managed manually, there are two possibilities. If the buffer was created
+ with an underlying "real" buffer through cluster_bp(), the mapping of the "real" buffer is returned.
+ Otherwise, the buffer was created with buf_alloc() and buf_setupl() was subsequently called; buf_map()
+ will call ubc_upl_map() to get a mapping for the buffer's upl and return the start of that mapping
+ plus the buffer's upl offset (set in buf_setupl()). In the last case, buf_unmap() must later be called
+ to tear down the mapping. NOTE: buf_map() does not set the buffer data pointer; this must be done with buf_setdataptr().
+ @param bp Buffer whose mapping to find or create.
+ @param io_addr Destination for mapping address.
+ @return 0 for success, ENOMEM if unable to map the buffer.
+ */
+errno_t buf_map(buf_t, caddr_t *);
+
+/*!
+ @function buf_unmap
+ @abstract Release mappings for buffer data.
+ @discussion For buffers created through buf_getblk() (i.e. traditional buffer cache usage),
+ buf_unmap() does nothing; buf_brelse() will take care of unmapping. For a B_CLUSTER buffer, i.e. an iobuf
+ whose upl state is managed manually, there are two possibilities. If the buffer was created
+ with an underlying "real" buffer through cluster_bp(), buf_unmap() does nothing; buf_brelse() on the
+ underlying buffer will tear down the mapping. Otherwise, the buffer was created with buf_alloc() and
+ buf_setupl() was subsequently called; buf_map() created the mapping. In this case, buf_unmap() will
+ unmap the buffer.
+ @param bp Buffer whose mapping to find or create.
+ @param io_addr Destination for mapping address.
+ @return 0 for success, EINVAL if unable to unmap buffer.
+ */
+errno_t buf_unmap(buf_t);
+
+/*!
+ @function buf_setdrvdata
+ @abstract Set driver-specific data on a buffer.
+ @param bp Buffer whose driver-data to set.
+ @param drvdata Opaque driver data.
+ @return void.
+ */
+void buf_setdrvdata(buf_t, void *);
+
+/*!
+ @function buf_setdrvdata
+ @abstract Get driver-specific data from a buffer.
+ @param bp Buffer whose driver data to get.
+ @return Opaque driver data.
+ */
+void * buf_drvdata(buf_t);
+
+/*!
+ @function buf_setfsprivate
+ @abstract Set filesystem-specific data on a buffer.
+ @param bp Buffer whose filesystem data to set.
+ @param fsprivate Opaque filesystem data.
+ @return void.
+ */
+void buf_setfsprivate(buf_t, void *);
+
+/*!
+ @function buf_fsprivate
+ @abstract Get filesystem-specific data from a buffer.
+ @param bp Buffer whose filesystem data to get.
+ @return Opaque filesystem data.
+ */
+void * buf_fsprivate(buf_t);
+
+/*!
+ @function buf_blkno
+ @abstract Get physical block number associated with a buffer, in the sense of VNOP_BLOCKMAP.
+ @discussion When a buffer's physical block number is the same is its logical block number, then the physical
+ block number is considered uninitialized. A physical block number of -1 indicates that there is no valid
+ physical mapping (e.g. the logical block is invalid or corresponds to a sparse region in a file). Physical
+ block number is normally set by the cluster layer or by buf_getblk().
+ @param bp Buffer whose physical block number to get.
+ @return Block number.
+ */
+daddr64_t buf_blkno(buf_t);
+
+/*!
+ @function buf_lblkno
+ @abstract Get logical block number associated with a buffer.
+ @discussion Logical block number is set on traditionally-used buffers by an argument passed to buf_getblk(),
+ for example by buf_bread().
+ @param bp Buffer whose logical block number to get.
+ @return Block number.
+ */
+daddr64_t buf_lblkno(buf_t);
+
+/*!
+ @function buf_setblkno
+ @abstract Set physical block number associated with a buffer.
+ @discussion Physical block number is generally set by the cluster layer or by buf_getblk().
+ @param bp Buffer whose physical block number to set.
+ @param blkno Block number to set.
+ @return void.
+ */
+void buf_setblkno(buf_t, daddr64_t);
+
+/*!
+ @function buf_setlblkno
+ @abstract Set logical block number associated with a buffer.
+ @discussion Logical block number is set on traditionally-used buffers by an argument passed to buf_getblk(),
+ for example by buf_bread().
+ @param bp Buffer whose logical block number to set.
+ @param lblkno Block number to set.
+ @return void.
+ */
+void buf_setlblkno(buf_t, daddr64_t);
+
+/*!
+ @function buf_count
+ @abstract Get count of valid bytes in a buffer. This may be less than the space allocated to the buffer.
+ @param bp Buffer whose byte count to get.
+ @return Byte count.
+ */
+uint32_t buf_count(buf_t);
+
+/*!
+ @function buf_size
+ @abstract Get size of data region allocated to a buffer.
+ @discussion May be larger than amount of valid data in buffer.
+ @param bp Buffer whose size to get.
+ @return Size.
+ */
+uint32_t buf_size(buf_t);
+
+/*!
+ @function buf_resid
+ @abstract Get a count of bytes which were not consumed by an I/O on a buffer.
+ @discussion Set when an I/O operations completes.
+ @param bp Buffer whose outstanding count to get.
+ @return Count of unwritten/unread bytes.
+ */
+uint32_t buf_resid(buf_t);
+
+/*!
+ @function buf_setcount
+ @abstract Set count of valid bytes in a buffer. This may be less than the space allocated to the buffer.
+ @param bp Buffer whose byte count to set.
+ @param bcount Count to set.
+ @return void.
projects / apple / xnu.git / blobdiff