Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
diff --git a/drivers/md/dm-io.c b/drivers/md/dm-io.c
new file mode 100644
index 0000000..45754bb
--- /dev/null
+++ b/drivers/md/dm-io.c
@@ -0,0 +1,426 @@
+/*
+ * Copyright (C) 2003 Sistina Software
+ *
+ * This file is released under the GPL.
+ */
+
+#include "dm-io.h"
+
+#include <linux/bio.h>
+#include <linux/mempool.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+
+static struct bio_set *_bios;
+
+/* FIXME: can we shrink this ? */
+struct io {
+ unsigned long error;
+ atomic_t count;
+ struct task_struct *sleeper;
+ io_notify_fn callback;
+ void *context;
+};
+
+/*
+ * io contexts are only dynamically allocated for asynchronous
+ * io. Since async io is likely to be the majority of io we'll
+ * have the same number of io contexts as buffer heads ! (FIXME:
+ * must reduce this).
+ */
+static unsigned _num_ios;
+static mempool_t *_io_pool;
+
+static void *alloc_io(unsigned int __nocast gfp_mask, void *pool_data)
+{
+ return kmalloc(sizeof(struct io), gfp_mask);
+}
+
+static void free_io(void *element, void *pool_data)
+{
+ kfree(element);
+}
+
+static unsigned int pages_to_ios(unsigned int pages)
+{
+ return 4 * pages; /* too many ? */
+}
+
+static int resize_pool(unsigned int new_ios)
+{
+ int r = 0;
+
+ if (_io_pool) {
+ if (new_ios == 0) {
+ /* free off the pool */
+ mempool_destroy(_io_pool);
+ _io_pool = NULL;
+ bioset_free(_bios);
+
+ } else {
+ /* resize the pool */
+ r = mempool_resize(_io_pool, new_ios, GFP_KERNEL);
+ }
+
+ } else {
+ /* create new pool */
+ _io_pool = mempool_create(new_ios, alloc_io, free_io, NULL);
+ if (!_io_pool)
+ return -ENOMEM;
+
+ _bios = bioset_create(16, 16, 4);
+ if (!_bios) {
+ mempool_destroy(_io_pool);
+ _io_pool = NULL;
+ return -ENOMEM;
+ }
+ }
+
+ if (!r)
+ _num_ios = new_ios;
+
+ return r;
+}
+
+int dm_io_get(unsigned int num_pages)
+{
+ return resize_pool(_num_ios + pages_to_ios(num_pages));
+}
+
+void dm_io_put(unsigned int num_pages)
+{
+ resize_pool(_num_ios - pages_to_ios(num_pages));
+}
+
+/*-----------------------------------------------------------------
+ * We need to keep track of which region a bio is doing io for.
+ * In order to save a memory allocation we store this the last
+ * bvec which we know is unused (blech).
+ * XXX This is ugly and can OOPS with some configs... find another way.
+ *---------------------------------------------------------------*/
+static inline void bio_set_region(struct bio *bio, unsigned region)
+{
+ bio->bi_io_vec[bio->bi_max_vecs - 1].bv_len = region;
+}
+
+static inline unsigned bio_get_region(struct bio *bio)
+{
+ return bio->bi_io_vec[bio->bi_max_vecs - 1].bv_len;
+}
+
+/*-----------------------------------------------------------------
+ * We need an io object to keep track of the number of bios that
+ * have been dispatched for a particular io.
+ *---------------------------------------------------------------*/
+static void dec_count(struct io *io, unsigned int region, int error)
+{
+ if (error)
+ set_bit(region, &io->error);
+
+ if (atomic_dec_and_test(&io->count)) {
+ if (io->sleeper)
+ wake_up_process(io->sleeper);
+
+ else {
+ int r = io->error;
+ io_notify_fn fn = io->callback;
+ void *context = io->context;
+
+ mempool_free(io, _io_pool);
+ fn(r, context);
+ }
+ }
+}
+
+static int endio(struct bio *bio, unsigned int done, int error)
+{
+ struct io *io = (struct io *) bio->bi_private;
+
+ /* keep going until we've finished */
+ if (bio->bi_size)
+ return 1;
+
+ if (error && bio_data_dir(bio) == READ)
+ zero_fill_bio(bio);
+
+ dec_count(io, bio_get_region(bio), error);
+ bio_put(bio);
+
+ return 0;
+}
+
+/*-----------------------------------------------------------------
+ * These little objects provide an abstraction for getting a new
+ * destination page for io.
+ *---------------------------------------------------------------*/
+struct dpages {
+ void (*get_page)(struct dpages *dp,
+ struct page **p, unsigned long *len, unsigned *offset);
+ void (*next_page)(struct dpages *dp);
+
+ unsigned context_u;
+ void *context_ptr;
+};
+
+/*
+ * Functions for getting the pages from a list.
+ */
+static void list_get_page(struct dpages *dp,
+ struct page **p, unsigned long *len, unsigned *offset)
+{
+ unsigned o = dp->context_u;
+ struct page_list *pl = (struct page_list *) dp->context_ptr;
+
+ *p = pl->page;
+ *len = PAGE_SIZE - o;
+ *offset = o;
+}
+
+static void list_next_page(struct dpages *dp)
+{
+ struct page_list *pl = (struct page_list *) dp->context_ptr;
+ dp->context_ptr = pl->next;
+ dp->context_u = 0;
+}
+
+static void list_dp_init(struct dpages *dp, struct page_list *pl, unsigned offset)
+{
+ dp->get_page = list_get_page;
+ dp->next_page = list_next_page;
+ dp->context_u = offset;
+ dp->context_ptr = pl;
+}
+
+/*
+ * Functions for getting the pages from a bvec.
+ */
+static void bvec_get_page(struct dpages *dp,
+ struct page **p, unsigned long *len, unsigned *offset)
+{
+ struct bio_vec *bvec = (struct bio_vec *) dp->context_ptr;
+ *p = bvec->bv_page;
+ *len = bvec->bv_len;
+ *offset = bvec->bv_offset;
+}
+
+static void bvec_next_page(struct dpages *dp)
+{
+ struct bio_vec *bvec = (struct bio_vec *) dp->context_ptr;
+ dp->context_ptr = bvec + 1;
+}
+
+static void bvec_dp_init(struct dpages *dp, struct bio_vec *bvec)
+{
+ dp->get_page = bvec_get_page;
+ dp->next_page = bvec_next_page;
+ dp->context_ptr = bvec;
+}
+
+static void vm_get_page(struct dpages *dp,
+ struct page **p, unsigned long *len, unsigned *offset)
+{
+ *p = vmalloc_to_page(dp->context_ptr);
+ *offset = dp->context_u;
+ *len = PAGE_SIZE - dp->context_u;
+}
+
+static void vm_next_page(struct dpages *dp)
+{
+ dp->context_ptr += PAGE_SIZE - dp->context_u;
+ dp->context_u = 0;
+}
+
+static void vm_dp_init(struct dpages *dp, void *data)
+{
+ dp->get_page = vm_get_page;
+ dp->next_page = vm_next_page;
+ dp->context_u = ((unsigned long) data) & (PAGE_SIZE - 1);
+ dp->context_ptr = data;
+}
+
+/*-----------------------------------------------------------------
+ * IO routines that accept a list of pages.
+ *---------------------------------------------------------------*/
+static void do_region(int rw, unsigned int region, struct io_region *where,
+ struct dpages *dp, struct io *io)
+{
+ struct bio *bio;
+ struct page *page;
+ unsigned long len;
+ unsigned offset;
+ unsigned num_bvecs;
+ sector_t remaining = where->count;
+
+ while (remaining) {
+ /*
+ * Allocate a suitably sized bio, we add an extra
+ * bvec for bio_get/set_region().
+ */
+ num_bvecs = (remaining / (PAGE_SIZE >> 9)) + 2;
+ bio = bio_alloc_bioset(GFP_NOIO, num_bvecs, _bios);
+ bio->bi_sector = where->sector + (where->count - remaining);
+ bio->bi_bdev = where->bdev;
+ bio->bi_end_io = endio;
+ bio->bi_private = io;
+ bio_set_region(bio, region);
+
+ /*
+ * Try and add as many pages as possible.
+ */
+ while (remaining) {
+ dp->get_page(dp, &page, &len, &offset);
+ len = min(len, to_bytes(remaining));
+ if (!bio_add_page(bio, page, len, offset))
+ break;
+
+ offset = 0;
+ remaining -= to_sector(len);
+ dp->next_page(dp);
+ }
+
+ atomic_inc(&io->count);
+ submit_bio(rw, bio);
+ }
+}
+
+static void dispatch_io(int rw, unsigned int num_regions,
+ struct io_region *where, struct dpages *dp,
+ struct io *io, int sync)
+{
+ int i;
+ struct dpages old_pages = *dp;
+
+ if (sync)
+ rw |= (1 << BIO_RW_SYNC);
+
+ /*
+ * For multiple regions we need to be careful to rewind
+ * the dp object for each call to do_region.
+ */
+ for (i = 0; i < num_regions; i++) {
+ *dp = old_pages;
+ if (where[i].count)
+ do_region(rw, i, where + i, dp, io);
+ }
+
+ /*
+ * Drop the extra refence that we were holding to avoid
+ * the io being completed too early.
+ */
+ dec_count(io, 0, 0);
+}
+
+static int sync_io(unsigned int num_regions, struct io_region *where,
+ int rw, struct dpages *dp, unsigned long *error_bits)
+{
+ struct io io;
+
+ if (num_regions > 1 && rw != WRITE) {
+ WARN_ON(1);
+ return -EIO;
+ }
+
+ io.error = 0;
+ atomic_set(&io.count, 1); /* see dispatch_io() */
+ io.sleeper = current;
+
+ dispatch_io(rw, num_regions, where, dp, &io, 1);
+
+ while (1) {
+ set_current_state(TASK_UNINTERRUPTIBLE);
+
+ if (!atomic_read(&io.count) || signal_pending(current))
+ break;
+
+ io_schedule();
+ }
+ set_current_state(TASK_RUNNING);
+
+ if (atomic_read(&io.count))
+ return -EINTR;
+
+ *error_bits = io.error;
+ return io.error ? -EIO : 0;
+}
+
+static int async_io(unsigned int num_regions, struct io_region *where, int rw,
+ struct dpages *dp, io_notify_fn fn, void *context)
+{
+ struct io *io;
+
+ if (num_regions > 1 && rw != WRITE) {
+ WARN_ON(1);
+ fn(1, context);
+ return -EIO;
+ }
+
+ io = mempool_alloc(_io_pool, GFP_NOIO);
+ io->error = 0;
+ atomic_set(&io->count, 1); /* see dispatch_io() */
+ io->sleeper = NULL;
+ io->callback = fn;
+ io->context = context;
+
+ dispatch_io(rw, num_regions, where, dp, io, 0);
+ return 0;
+}
+
+int dm_io_sync(unsigned int num_regions, struct io_region *where, int rw,
+ struct page_list *pl, unsigned int offset,
+ unsigned long *error_bits)
+{
+ struct dpages dp;
+ list_dp_init(&dp, pl, offset);
+ return sync_io(num_regions, where, rw, &dp, error_bits);
+}
+
+int dm_io_sync_bvec(unsigned int num_regions, struct io_region *where, int rw,
+ struct bio_vec *bvec, unsigned long *error_bits)
+{
+ struct dpages dp;
+ bvec_dp_init(&dp, bvec);
+ return sync_io(num_regions, where, rw, &dp, error_bits);
+}
+
+int dm_io_sync_vm(unsigned int num_regions, struct io_region *where, int rw,
+ void *data, unsigned long *error_bits)
+{
+ struct dpages dp;
+ vm_dp_init(&dp, data);
+ return sync_io(num_regions, where, rw, &dp, error_bits);
+}
+
+int dm_io_async(unsigned int num_regions, struct io_region *where, int rw,
+ struct page_list *pl, unsigned int offset,
+ io_notify_fn fn, void *context)
+{
+ struct dpages dp;
+ list_dp_init(&dp, pl, offset);
+ return async_io(num_regions, where, rw, &dp, fn, context);
+}
+
+int dm_io_async_bvec(unsigned int num_regions, struct io_region *where, int rw,
+ struct bio_vec *bvec, io_notify_fn fn, void *context)
+{
+ struct dpages dp;
+ bvec_dp_init(&dp, bvec);
+ return async_io(num_regions, where, rw, &dp, fn, context);
+}
+
+int dm_io_async_vm(unsigned int num_regions, struct io_region *where, int rw,
+ void *data, io_notify_fn fn, void *context)
+{
+ struct dpages dp;
+ vm_dp_init(&dp, data);
+ return async_io(num_regions, where, rw, &dp, fn, context);
+}
+
+EXPORT_SYMBOL(dm_io_get);
+EXPORT_SYMBOL(dm_io_put);
+EXPORT_SYMBOL(dm_io_sync);
+EXPORT_SYMBOL(dm_io_async);
+EXPORT_SYMBOL(dm_io_sync_bvec);
+EXPORT_SYMBOL(dm_io_async_bvec);
+EXPORT_SYMBOL(dm_io_sync_vm);
+EXPORT_SYMBOL(dm_io_async_vm);
