From 8b2458f413c429e4c5c4799e02ec2820396aaac4 Mon Sep 17 00:00:00 2001 From: Alexander Usyskin Date: Thu, 7 Jan 2016 14:46:37 +0200 Subject: [PATCH] mei: always copy the read buffer if data is ready Copy completed callback content to the user space if we have such callback ready in the beginning of the read. Simplify offset processing logic as byproduct. This is a refinement for: commit 139aacf757fc ("mei: fix read after read scenario") Signed-off-by: Alexander Usyskin Signed-off-by: Tomas Winkler Signed-off-by: Greg Kroah-Hartman --- drivers/misc/mei/main.c | 32 ++++++++++++++------------------ 1 file changed, 14 insertions(+), 18 deletions(-) diff --git a/drivers/misc/mei/main.c b/drivers/misc/mei/main.c index 677d0362..36ca152 100644 --- a/drivers/misc/mei/main.c +++ b/drivers/misc/mei/main.c @@ -159,27 +159,22 @@ static ssize_t mei_read(struct file *file, char __user *ubuf, goto out; } + if (ubuf == NULL) { + rets = -EMSGSIZE; + goto out; + } + if (cl == &dev->iamthif_cl) { rets = mei_amthif_read(dev, file, ubuf, length, offset); goto out; } cb = mei_cl_read_cb(cl, file); - if (cb) { - /* read what left */ - if (cb->buf_idx > *offset) - goto copy_buffer; - /* offset is beyond buf_idx we have no more data return 0 */ - if (cb->buf_idx > 0 && cb->buf_idx <= *offset) { - rets = 0; - goto free; - } - /* Offset needs to be cleaned for contiguous reads*/ - if (cb->buf_idx == 0 && *offset > 0) - *offset = 0; - } else if (*offset > 0) { + if (cb) + goto copy_buffer; + + if (*offset > 0) *offset = 0; - } err = mei_cl_read_start(cl, length, file); if (err && err != -EBUSY) { @@ -231,10 +226,10 @@ copy_buffer: goto free; } - cl_dbg(dev, cl, "buf.size = %d buf.idx = %ld\n", - cb->buf.size, cb->buf_idx); - if (length == 0 || ubuf == NULL || *offset > cb->buf_idx) { - rets = -EMSGSIZE; + cl_dbg(dev, cl, "buf.size = %d buf.idx = %ld offset = %lld\n", + cb->buf.size, cb->buf_idx, *offset); + if (*offset >= cb->buf_idx) { + rets = 0; goto free; } @@ -255,6 +250,7 @@ copy_buffer: free: mei_io_cb_free(cb); + *offset = 0; out: cl_dbg(dev, cl, "end mei read rets = %d\n", rets); -- 2.7.4