ll_rw_block (9) - Linux Manuals

ll_rw_block: level access to block devices (DEPRECATED)

NAME

ll_rw_block - level access to block devices (DEPRECATED)

SYNOPSIS

void ll_rw_block(int op, int op_flags, int nr, struct buffer_head * bhs[]);

ARGUMENTS

op

whether to READ or WRITE

op_flags

rq_flag_bits

nr

number of struct buffer_heads in the array

bhs[]

array of pointers to struct buffer_head

DESCRIPTION

ll_rw_block takes an array of pointers to struct buffer_heads, and requests an I/O operation on them, either a REQ_OP_READ or a REQ_OP_WRITE. op_flags contains flags modifying the detailed I/O behavior, most notably REQ_RAHEAD.

This function drops any buffer that it cannot get a lock on (with the BH_Lock state bit), any buffer that appears to be clean when doing a write request, and any buffer that appears to be up-to-date when doing read request. Further it marks as clean buffers that are processed for writing (the buffer cache won't assume that they are actually clean until the buffer gets unlocked).

ll_rw_block sets b_end_io to simple completion handler that marks the buffer up-to-date (if appropriate), unlocks the buffer and wakes any waiters.

All of the buffers must be for the same device, and must also be a multiple of the current approved size for the device.

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