cifs: convert async read code to use pages array without kmapping

Replace the "marshal_iov" function with a "read_into_pages" function.
That function will copy the read data off the socket and into the
pages array, kmapping and reading pages one at a time.

Signed-off-by: Jeff Layton <jlayton@redhat.com>

1 files changed, 60 insertions, 61 deletions

diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 6eaf482..f3f1b10 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -2566,63 +2566,57 @@ cifs_uncached_readv_complete(struct work_struct *work)
 {
 	struct cifs_readdata *rdata = container_of(work,
 						struct cifs_readdata, work);
-	unsigned int i;
-
-	/* if the result is non-zero then the pages weren't kmapped */
-	if (rdata->result == 0) {
-		for (i = 0; i < rdata->nr_pages; i++)
-			kunmap(rdata->pages[i]);
-	}
 
 	complete(&rdata->done);
 	kref_put(&rdata->refcount, cifs_uncached_readdata_release);
 }
 
 static int
-cifs_uncached_read_marshal_iov(struct cifs_readdata *rdata,
-				unsigned int remaining)
+cifs_uncached_read_into_pages(struct TCP_Server_Info *server,
+			struct cifs_readdata *rdata, unsigned int len)
 {
-	int len = 0;
+	int total_read = 0, result = 0;
 	unsigned int i;
 	unsigned int nr_pages = rdata->nr_pages;
+	struct kvec iov;
 
-	rdata->nr_iov = 1;
+	rdata->tailsz = PAGE_SIZE;
 	for (i = 0; i < nr_pages; i++) {
 		struct page *page = rdata->pages[i];
 
-		if (remaining >= PAGE_SIZE) {
+		if (len >= PAGE_SIZE) {
 			/* enough data to fill the page */
-			rdata->iov[rdata->nr_iov].iov_base = kmap(page);
-			rdata->iov[rdata->nr_iov].iov_len = PAGE_SIZE;
-			cFYI(1, "%u: idx=%lu iov_base=%p iov_len=%zu",
-				rdata->nr_iov, page->index,
-				rdata->iov[rdata->nr_iov].iov_base,
-				rdata->iov[rdata->nr_iov].iov_len);
-			++rdata->nr_iov;
-			len += PAGE_SIZE;
-			remaining -= PAGE_SIZE;
-		} else if (remaining > 0) {
+			iov.iov_base = kmap(page);
+			iov.iov_len = PAGE_SIZE;
+			cFYI(1, "%u: iov_base=%p iov_len=%zu",
+				i, iov.iov_base, iov.iov_len);
+			len -= PAGE_SIZE;
+		} else if (len > 0) {
 			/* enough for partial page, fill and zero the rest */
-			rdata->iov[rdata->nr_iov].iov_base = kmap(page);
-			rdata->iov[rdata->nr_iov].iov_len = remaining;
-			cFYI(1, "%u: idx=%lu iov_base=%p iov_len=%zu",
-				rdata->nr_iov, page->index,
-				rdata->iov[rdata->nr_iov].iov_base,
-				rdata->iov[rdata->nr_iov].iov_len);
-			memset(rdata->iov[rdata->nr_iov].iov_base + remaining,
-				'\0', PAGE_SIZE - remaining);
-			++rdata->nr_iov;
-			len += remaining;
-			remaining = 0;
+			iov.iov_base = kmap(page);
+			iov.iov_len = len;
+			cFYI(1, "%u: iov_base=%p iov_len=%zu",
+				i, iov.iov_base, iov.iov_len);
+			memset(iov.iov_base + len, '\0', PAGE_SIZE - len);
+			rdata->tailsz = len;
+			len = 0;
 		} else {
 			/* no need to hold page hostage */
 			rdata->pages[i] = NULL;
 			rdata->nr_pages--;
 			put_page(page);
+			continue;
 		}
+
+		result = cifs_readv_from_socket(server, &iov, 1, iov.iov_len);
+		kunmap(page);
+		if (result < 0)
+			break;
+
+		total_read += result;
 	}
 
-	return len;
+	return total_read > 0 ? total_read : result;
 }
 
 static ssize_t
@@ -2685,7 +2679,8 @@ cifs_iovec_read(struct file *file, const struct iovec *iov,
 		rdata->offset = offset;
 		rdata->bytes = cur_len;
 		rdata->pid = pid;
-		rdata->marshal_iov = cifs_uncached_read_marshal_iov;
+		rdata->pagesz = PAGE_SIZE;
+		rdata->read_into_pages = cifs_uncached_read_into_pages;
 
 		rc = cifs_retry_async_readv(rdata);
 error:
@@ -2935,7 +2930,6 @@ cifs_readv_complete(struct work_struct *work)
 		lru_cache_add_file(page);
 
 		if (rdata->result == 0) {
-			kunmap(page);
 			flush_dcache_page(page);
 			SetPageUptodate(page);
 		}
@@ -2952,47 +2946,42 @@ cifs_readv_complete(struct work_struct *work)
 }
 
 static int
-cifs_readpages_marshal_iov(struct cifs_readdata *rdata, unsigned int remaining)
+cifs_readpages_read_into_pages(struct TCP_Server_Info *server,
+			struct cifs_readdata *rdata, unsigned int len)
 {
-	int len = 0;
+	int total_read = 0, result = 0;
 	unsigned int i;
 	u64 eof;
 	pgoff_t eof_index;
 	unsigned int nr_pages = rdata->nr_pages;
+	struct kvec iov;
 
 	/* determine the eof that the server (probably) has */
 	eof = CIFS_I(rdata->mapping->host)->server_eof;
 	eof_index = eof ? (eof - 1) >> PAGE_CACHE_SHIFT : 0;
 	cFYI(1, "eof=%llu eof_index=%lu", eof, eof_index);
 
-	rdata->nr_iov = 1;
+	rdata->tailsz = PAGE_CACHE_SIZE;
 	for (i = 0; i < nr_pages; i++) {
 		struct page *page = rdata->pages[i];
 
-		if (remaining >= PAGE_CACHE_SIZE) {
+		if (len >= PAGE_CACHE_SIZE) {
 			/* enough data to fill the page */
-			rdata->iov[rdata->nr_iov].iov_base = kmap(page);
-			rdata->iov[rdata->nr_iov].iov_len = PAGE_CACHE_SIZE;
+			iov.iov_base = kmap(page);
+			iov.iov_len = PAGE_CACHE_SIZE;
 			cFYI(1, "%u: idx=%lu iov_base=%p iov_len=%zu",
-				rdata->nr_iov, page->index,
-				rdata->iov[rdata->nr_iov].iov_base,
-				rdata->iov[rdata->nr_iov].iov_len);
-			++rdata->nr_iov;
-			len += PAGE_CACHE_SIZE;
-			remaining -= PAGE_CACHE_SIZE;
-		} else if (remaining > 0) {
+				i, page->index, iov.iov_base, iov.iov_len);
+			len -= PAGE_CACHE_SIZE;
+		} else if (len > 0) {
 			/* enough for partial page, fill and zero the rest */
-			rdata->iov[rdata->nr_iov].iov_base = kmap(page);
-			rdata->iov[rdata->nr_iov].iov_len = remaining;
+			iov.iov_base = kmap(page);
+			iov.iov_len = len;
 			cFYI(1, "%u: idx=%lu iov_base=%p iov_len=%zu",
-				rdata->nr_iov, page->index,
-				rdata->iov[rdata->nr_iov].iov_base,
-				rdata->iov[rdata->nr_iov].iov_len);
-			memset(rdata->iov[rdata->nr_iov].iov_base + remaining,
-				'\0', PAGE_CACHE_SIZE - remaining);
-			++rdata->nr_iov;
-			len += remaining;
-			remaining = 0;
+				i, page->index, iov.iov_base, iov.iov_len);
+			memset(iov.iov_base + len,
+				'\0', PAGE_CACHE_SIZE - len);
+			rdata->tailsz = len;
+			len = 0;
 		} else if (page->index > eof_index) {
 			/*
 			 * The VFS will not try to do readahead past the
@@ -3010,6 +2999,7 @@ cifs_readpages_marshal_iov(struct cifs_readdata *rdata, unsigned int remaining)
 			page_cache_release(page);
 			rdata->pages[i] = NULL;
 			rdata->nr_pages--;
+			continue;
 		} else {
 			/* no need to hold page hostage */
 			lru_cache_add_file(page);
@@ -3017,10 +3007,18 @@ cifs_readpages_marshal_iov(struct cifs_readdata *rdata, unsigned int remaining)
 			page_cache_release(page);
 			rdata->pages[i] = NULL;
 			rdata->nr_pages--;
+			continue;
 		}
+
+		result = cifs_readv_from_socket(server, &iov, 1, iov.iov_len);
+		kunmap(page);
+		if (result < 0)
+			break;
+
+		total_read += result;
 	}
 
-	return len;
+	return total_read > 0 ? total_read : result;
 }
 
 static int cifs_readpages(struct file *file, struct address_space *mapping,
@@ -3144,7 +3142,8 @@ static int cifs_readpages(struct file *file, struct address_space *mapping,
 		rdata->offset = offset;
 		rdata->bytes = bytes;
 		rdata->pid = pid;
-		rdata->marshal_iov = cifs_readpages_marshal_iov;
+		rdata->pagesz = PAGE_CACHE_SIZE;
+		rdata->read_into_pages = cifs_readpages_read_into_pages;
 
 		list_for_each_entry_safe(page, tpage, &tmplist, lru) {
 			list_del(&page->lru);