There are cases outside of our control that may result in a transmit
skb being linearized in dev_queue_xmit. There are a couple of bugs
in libfc/fcoe that can result in a panic at that point. This patch
contains two fixes to prevent those panics.
1) use fast cloning instead of shared skbs with dev_queue_xmit
dev_queue_xmit doen't want shared skbuffs being passed in, and
__skb_linearize will BUG if the skb is shared. FCoE is holding an extra
reference around the call to dev_queue_xmit, so that when it returns an
error code indicating the frame has been dropped it can maintain it's
own backlog and retransmit. Switch to using fast skb cloning for this
instead.
2) don't append compound pages as > PAGE_SIZE skb fragments
fc_fcp_send_data will append pages from a scatterlist to the nr_frags[]
if the netdev supports it. But, it's using > PAGE_SIZE compound pages
as a single skb_frag. In the highmem linearize case that page will be
passed to kmap_atomic to get a mapping to copy out of, but
kmap_atomic will only allow access to the first PAGE_SIZE part.
The memcpy will keep going and cause a page fault once is crosses the
first boundary.
If fc_fcp_send_data uses linear buffers from the start, it calls
kmap_atomic one PAGE_SIZE at a time. That same logic needs to be
applied when setting up skb_frags.
Signed-off-by: Chris Leech <christopher.leech@intel.com>
Signed-off-by: Robert Love <robert.w.love@intel.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
Cleans up frame allocation APIs to have just single fc_frame_alloc API.
Removes _fc_frame_alloc, renames __fc_frame_alloc to _fc_frame_alloc.
Modifies fc_fcp_send_data for removed _fc_frame_alloc, fc_fcp_send_data
was the only user of removed _fc_frame_alloc.
Also Adds check in fc_frame_alloc to do mod by 4 for only non-zero
len value.
This patch is prep work to fix can_queue reducing in next patch.
Single fc_frame_alloc API helps in fixing can_queue reducing in
next patch.
Signed-off-by: Vasu Dev <vasu.dev@intel.com>
Signed-off-by: Robert Love <robert.w.love@intel.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
Allow a vport specific string to be appended to the port symbolic
name. The new symbolic name is sent to the name server after it
is set.
This currently messes with libhbalinux, which is looking for
the fcoe "fcoe <ver> over <ethX>" string and expects whatever
comes after the "over" to be a network interface name only.
Adds an EXPORT_SYMBOL to libfc for fc_frame_alloc_fill, which is
needed to allow fcoe to allocate a frame of variable length for
the RSPN request.
Signed-off-by: Chris Leech <christopher.leech@intel.com>
Signed-off-by: Robert Love <robert.w.love@intel.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
These are a few functions that were not used by other
modules. They did not need to be exported so this patch
removes the EXPORT_SYMBOLS call for each.
Signed-off-by: Robert Love <robert.w.love@intel.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
libFC is composed of 4 blocks supported by an exchange manager
and a framing library. The upper 4 layers are fc_lport, fc_disc,
fc_rport and fc_fcp. A LLD that uses libfc could choose to
either use libfc's block, or using the transport template
defined in libfc.h, override one or more blocks with its own
implementation.
The EM (Exchange Manager) manages exhcanges/sequences for all
commands- ELS, CT and FCP.
The framing library frames ELS and CT commands.
The fc_lport block manages the library's representation of the
host's FC enabled ports.
The fc_disc block manages discovery of targets as well as
handling changes that occur in the FC fabric (via. RSCN events).
The fc_rport block manages the library's representation of other
entities in the FC fabric. Currently the library uses this block
for targets, its peer when in point-to-point mode and the
directory server, but can be extended for other entities if
needed.
The fc_fcp block interacts with the scsi-ml and handles all
I/O.
Signed-off-by: Robert Love <robert.w.love@intel.com>
[jejb: added include of delay.h to fix ppc64 compile prob spotted by sfr]
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Chris Leech
Vasu Dev
Robert Love