[JFFS2] Optimise reading of eraseblock summary nodes
This improves the time to mount 512MiB of NAND flash on my OLPC prototype by about 4%. We used to read the last page of the eraseblock twice -- once to find the offset of the summary node, and again to actually _read_ the summary node. Now we read the last page only once, and read more only if we need to. We also don't allocate a new buffer just for the summary code -- we use the buffer which was already allocated for the scan. Better still, if the 'buffer' for the scan is actually just a pointer directly into NOR flash, we use that too, avoiding the memcpy() which we used to do. Signed-off-by: David Woodhouse <dwmw2@infradead.org>
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parent
6c8b44abc8
commit
9641b784ff
3 changed files with 66 additions and 51 deletions
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@ -306,11 +306,12 @@ int jffs2_scan_classify_jeb(struct jffs2_sb_info *c, struct jffs2_eraseblock *je
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return BLK_STATE_ALLDIRTY;
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}
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/* Called with 'buf_size == 0' if buf is in fact a pointer _directly_ into
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the flash, XIP-style */
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static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
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unsigned char *buf, uint32_t buf_size, struct jffs2_summary *s) {
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unsigned char *buf, uint32_t buf_size, struct jffs2_summary *s) {
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struct jffs2_unknown_node *node;
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struct jffs2_unknown_node crcnode;
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struct jffs2_sum_marker *sm;
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uint32_t ofs, prevofs;
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uint32_t hdr_crc, buf_ofs, buf_len;
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int err;
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@ -344,32 +345,69 @@ static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblo
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#endif
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if (jffs2_sum_active()) {
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sm = kmalloc(sizeof(struct jffs2_sum_marker), GFP_KERNEL);
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if (!sm) {
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return -ENOMEM;
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}
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err = jffs2_fill_scan_buf(c, (unsigned char *) sm, jeb->offset + c->sector_size -
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sizeof(struct jffs2_sum_marker), sizeof(struct jffs2_sum_marker));
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if (err) {
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kfree(sm);
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return err;
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}
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if (je32_to_cpu(sm->magic) == JFFS2_SUM_MAGIC ) {
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err = jffs2_sum_scan_sumnode(c, jeb, je32_to_cpu(sm->offset), &pseudo_random);
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if (err) {
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kfree(sm);
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return err;
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struct jffs2_sum_marker *sm;
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void *sumptr = NULL;
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uint32_t sumlen;
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if (!buf_size) {
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/* XIP case. Just look, point at the summary if it's there */
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sm = (void *)buf + jeb->offset - sizeof(*sm);
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if (je32_to_cpu(sm->magic) == JFFS2_SUM_MAGIC) {
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sumptr = buf + je32_to_cpu(sm->offset);
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sumlen = c->sector_size - je32_to_cpu(sm->offset);
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}
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} else {
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/* If NAND flash, read a whole page of it. Else just the end */
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if (c->wbuf_pagesize)
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buf_len = c->wbuf_pagesize;
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else
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buf_len = sizeof(*sm);
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/* Read as much as we want into the _end_ of the preallocated buffer */
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err = jffs2_fill_scan_buf(c, buf + buf_size - buf_len,
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jeb->offset + c->sector_size - buf_len,
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buf_len);
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if (err)
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return err;
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sm = (void *)buf + buf_size - sizeof(*sm);
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if (je32_to_cpu(sm->magic) == JFFS2_SUM_MAGIC) {
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sumlen = c->sector_size - je32_to_cpu(sm->offset);
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sumptr = buf + buf_size - sumlen;
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/* Now, make sure the summary itself is available */
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if (sumlen > buf_size) {
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/* Need to kmalloc for this. */
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sumptr = kmalloc(sumlen, GFP_KERNEL);
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if (!sumptr)
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return -ENOMEM;
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memcpy(sumptr + sumlen - buf_len, buf + buf_size - buf_len, buf_len);
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}
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if (buf_len < sumlen) {
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/* Need to read more so that the entire summary node is present */
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err = jffs2_fill_scan_buf(c, sumptr,
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jeb->offset + c->sector_size - sumlen,
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sumlen - buf_len);
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if (err)
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return err;
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}
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}
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}
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kfree(sm);
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if (sumptr) {
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err = jffs2_sum_scan_sumnode(c, jeb, sumptr, sumlen, &pseudo_random);
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if (err)
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return err;
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if (buf_size && sumlen > buf_size)
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kfree(sumptr);
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}
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}
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buf_ofs = jeb->offset;
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if (!buf_size) {
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/* This is the XIP case -- we're reading _directly_ from the flash chip */
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buf_len = c->sector_size;
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} else {
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buf_len = EMPTY_SCAN_SIZE(c->sector_size);
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@ -318,7 +318,6 @@ static int jffs2_sum_process_sum_data(struct jffs2_sb_info *c, struct jffs2_eras
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raw = jffs2_alloc_raw_node_ref();
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if (!raw) {
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JFFS2_NOTICE("allocation of node reference failed\n");
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kfree(summary);
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return -ENOMEM;
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}
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@ -326,7 +325,6 @@ static int jffs2_sum_process_sum_data(struct jffs2_sb_info *c, struct jffs2_eras
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if (!ic) {
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JFFS2_NOTICE("scan_make_ino_cache failed\n");
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jffs2_free_raw_node_ref(raw);
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kfree(summary);
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return -ENOMEM;
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}
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@ -358,10 +356,8 @@ static int jffs2_sum_process_sum_data(struct jffs2_sb_info *c, struct jffs2_eras
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jeb->offset + je32_to_cpu(spd->offset));
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fd = jffs2_alloc_full_dirent(spd->nsize+1);
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if (!fd) {
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kfree(summary);
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if (!fd)
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return -ENOMEM;
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}
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memcpy(&fd->name, spd->name, spd->nsize);
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fd->name[spd->nsize] = 0;
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@ -370,7 +366,6 @@ static int jffs2_sum_process_sum_data(struct jffs2_sb_info *c, struct jffs2_eras
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if (!raw) {
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jffs2_free_full_dirent(fd);
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JFFS2_NOTICE("allocation of node reference failed\n");
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kfree(summary);
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return -ENOMEM;
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}
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@ -378,7 +373,6 @@ static int jffs2_sum_process_sum_data(struct jffs2_sb_info *c, struct jffs2_eras
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if (!ic) {
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jffs2_free_full_dirent(fd);
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jffs2_free_raw_node_ref(raw);
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kfree(summary);
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return -ENOMEM;
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}
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@ -411,45 +405,28 @@ static int jffs2_sum_process_sum_data(struct jffs2_sb_info *c, struct jffs2_eras
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default : {
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JFFS2_WARNING("Unsupported node type found in summary! Exiting...");
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kfree(summary);
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return -EIO;
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}
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}
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}
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kfree(summary);
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return 0;
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}
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/* Process the summary node - called from jffs2_scan_eraseblock() */
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int jffs2_sum_scan_sumnode(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
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uint32_t ofs, uint32_t *pseudo_random)
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struct jffs2_raw_summary *summary, uint32_t sumsize,
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uint32_t *pseudo_random)
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{
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struct jffs2_unknown_node crcnode;
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struct jffs2_raw_node_ref *cache_ref;
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struct jffs2_raw_summary *summary;
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int ret, sumsize;
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int ret, ofs;
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uint32_t crc;
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sumsize = c->sector_size - ofs;
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ofs += jeb->offset;
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ofs = jeb->offset + c->sector_size - sumsize;
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dbg_summary("summary found for 0x%08x at 0x%08x (0x%x bytes)\n",
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jeb->offset, ofs, sumsize);
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summary = kmalloc(sumsize, GFP_KERNEL);
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if (!summary) {
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return -ENOMEM;
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}
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ret = jffs2_fill_scan_buf(c, (unsigned char *)summary, ofs, sumsize);
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if (ret) {
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kfree(summary);
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return ret;
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}
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jeb->offset, ofs, sumsize);
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/* OK, now check for node validity and CRC */
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crcnode.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
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@ -499,7 +476,6 @@ int jffs2_sum_scan_sumnode(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb
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if (!marker_ref) {
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JFFS2_NOTICE("Failed to allocate node ref for clean marker\n");
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kfree(summary);
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return -ENOMEM;
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}
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@ -160,7 +160,8 @@ int jffs2_sum_add_padding_mem(struct jffs2_summary *s, uint32_t size);
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int jffs2_sum_add_inode_mem(struct jffs2_summary *s, struct jffs2_raw_inode *ri, uint32_t ofs);
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int jffs2_sum_add_dirent_mem(struct jffs2_summary *s, struct jffs2_raw_dirent *rd, uint32_t ofs);
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int jffs2_sum_scan_sumnode(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
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uint32_t ofs, uint32_t *pseudo_random);
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struct jffs2_raw_summary *summary, uint32_t sumlen,
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uint32_t *pseudo_random);
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#else /* SUMMARY DISABLED */
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