diff options
| author | David Howells <dhowells@redhat.com> | 2024-12-16 20:40:55 +0000 |
|---|---|---|
| committer | Christian Brauner <brauner@kernel.org> | 2024-12-20 22:34:02 +0100 |
| commit | 06fa229ceb36898e68022b5654c017d2c6582d7d (patch) | |
| tree | db540d16164012b660f6096819f5288356749f39 /include/linux/netfs.h | |
| parent | aabcabf2746062253565b33aa3f8d25999a5ac01 (diff) | |
netfs: Abstract out a rolling folio buffer implementation
A rolling buffer is a series of folios held in a list of folio_queues. New
folios and folio_queue structs may be inserted at the head simultaneously
with spent ones being removed from the tail without the need for locking.
The rolling buffer includes an iov_iter and it has to be careful managing
this as the list of folio_queues is extended such that an oops doesn't
incurred because the iterator was pointing to the end of a folio_queue
segment that got appended to and then removed.
We need to use the mechanism twice, once for read and once for write, and,
in future patches, we will use a second rolling buffer to handle bounce
buffering for content encryption.
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/20241216204124.3752367-6-dhowells@redhat.com
cc: Jeff Layton <jlayton@kernel.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
Diffstat (limited to 'include/linux/netfs.h')
| -rw-r--r-- | include/linux/netfs.h | 10 |
1 files changed, 4 insertions, 6 deletions
diff --git a/include/linux/netfs.h b/include/linux/netfs.h index 5b2f427f8e3e..bd922f0936e3 100644 --- a/include/linux/netfs.h +++ b/include/linux/netfs.h @@ -18,6 +18,7 @@ #include <linux/fs.h> #include <linux/pagemap.h> #include <linux/uio.h> +#include <linux/rolling_buffer.h> enum netfs_sreq_ref_trace; typedef struct mempool_s mempool_t; @@ -238,10 +239,9 @@ struct netfs_io_request { struct netfs_io_stream io_streams[2]; /* Streams of parallel I/O operations */ #define NR_IO_STREAMS 2 //wreq->nr_io_streams struct netfs_group *group; /* Writeback group being written back */ - struct folio_queue *buffer; /* Head of I/O buffer */ - struct folio_queue *buffer_tail; /* Tail of I/O buffer */ - struct iov_iter iter; /* Unencrypted-side iterator */ - struct iov_iter io_iter; /* I/O (Encrypted-side) iterator */ + struct rolling_buffer buffer; /* Unencrypted buffer */ +#define NETFS_ROLLBUF_PUT_MARK ROLLBUF_MARK_1 +#define NETFS_ROLLBUF_PAGECACHE_MARK ROLLBUF_MARK_2 void *netfs_priv; /* Private data for the netfs */ void *netfs_priv2; /* Private data for the netfs */ struct bio_vec *direct_bv; /* DIO buffer list (when handling iovec-iter) */ @@ -259,8 +259,6 @@ struct netfs_io_request { long error; /* 0 or error that occurred */ enum netfs_io_origin origin; /* Origin of the request */ bool direct_bv_unpin; /* T if direct_bv[] must be unpinned */ - u8 buffer_head_slot; /* First slot in ->buffer */ - u8 buffer_tail_slot; /* Next slot in ->buffer_tail */ unsigned long long i_size; /* Size of the file */ unsigned long long start; /* Start position */ atomic64_t issued_to; /* Write issuer folio cursor */ |