sfc: fix considering that all channels have TX queues

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: sfc: fix considering that all channels have TX queues Normally, all channels have RX and TX queues, but this is not true if modparam efx_separate_tx_channels=1 is used. In that cases, some channels only have RX queues and others only TX queues (or more preciselly, they have them allocated, but not initialized). Fix efx_channel_has_tx_queues to return the correct value for this case too. Messages shown at probe time before the fix: sfc 0000:03:00.0 ens6f0np0: MC command 0x82 inlen 544 failed rc=-22 (raw=0) arg=0 ------------[ cut here ]------------ netdevice: ens6f0np0: failed to initialise TXQ -1 WARNING: CPU: 1 PID: 626 at drivers/net/ethernet/sfc/ef10.c:2393 efx_ef10_tx_init+0x201/0x300 [sfc] [...] stripped RIP: 0010:efx_ef10_tx_init+0x201/0x300 [sfc] [...] stripped Call Trace: efx_init_tx_queue+0xaa/0xf0 [sfc] efx_start_channels+0x49/0x120 [sfc] efx_start_all+0x1f8/0x430 [sfc] efx_net_open+0x5a/0xe0 [sfc] __dev_open+0xd0/0x190 __dev_change_flags+0x1b3/0x220 dev_change_flags+0x21/0x60 [...] stripped Messages shown at remove time before the fix: sfc 0000:03:00.0 ens6f0np0: failed to flush 10 queues sfc 0000:03:00.0 ens6f0np0: failed to flush queues

References

• https://git.kernel.org/stable/c/8f81a4113e1e574d2cbde4f2cd599380a9189c0f
• https://git.kernel.org/stable/c/5567d69b95b9c07e1c56f15cf0301251d12e5f97
• https://git.kernel.org/stable/c/e7e8d5e25dc762b70f9c88ec6b7d451d0816eead
• https://git.kernel.org/stable/c/913d45f02d346ce41c4aad057eaf53a8ed449dc3
• https://git.kernel.org/stable/c/2e102b53f8a778f872dc137f4c7ac548705817aa