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purex_item.iocb is defined as a 64-element u8 array, but 64 is the minimum size and it can be allocated larger. This makes it a standard empty flex array. This was motivated by field-spanning write warnings during FPIN testing: https://lore.kernel.org/linux-nvme/20250709211919.49100-1-bgurney@redhat.com/ > kernel: memcpy: detected field-spanning write (size 60) of single field > "((uint8_t *)fpin_pkt + buffer_copy_offset)" > at drivers/scsi/qla2xxx/qla_isr.c:1221 (size 44) I removed the outer wrapper from the iocb flex array, so that it can be linked to 'purex_item.size' with '__counted_by'. These changes remove the default minimum 64-byte allocation, requiring further changes. In 'struct scsi_qla_host' the embedded 'default_item' is now followed by '__default_item_iocb[QLA_DEFAULT_PAYLOAD_SIZE]' to reserve space that will be used as 'default_item.iocb'. This is wrapped using the 'TRAILING_OVERLAP()' macro helper, which effectively creates a union between flexible-array member 'default_item.iocb' and '__default_item_iocb'. Since 'struct pure_item' now contains a flexible-array member, the helper must be placed at the end of 'struct scsi_qla_host' to prevent a '-Wflex-array-member-not-at-end' warning. 'qla24xx_alloc_purex_item()' is adjusted to no longer expect the default minimum size to be part of 'sizeof(struct purex_item)', the entire flexible array size is added to the structure size for allocation. This also slightly changes the layout of the purex_item struct, as 2-bytes of padding are added between 'size' and 'iocb'. The resulting size is the same, but iocb is shifted 2-bytes (the original 'purex_item' structure was padded at the end, after the 64-byte defined array size). I don't think this is a problem. Tested-by: Bryan Gurney <bgurney@redhat.com> Co-developed-by: Chris Leech <cleech@redhat.com> Signed-off-by: Chris Leech <cleech@redhat.com> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> Link: https://lore.kernel.org/r/20250813200744.17975-10-bgurney@redhat.com Reviewed-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> [ commit 6f4b10226b6b upstream ]
Overview
This is the source code repository of the SCST project. SCST is a collection of Linux kernel drivers that implement SCSI target functionality. The SCST project includes:
- The SCST core in the scst/ subdirectory.
- A tool for loading, saving and modifying the SCST configuration in directory scstadmin/.
- Several SCSI target drivers in the directories iscsi-scst/, qla2x00t/, srpt/, scst_local/ and fcst/.
- User space programs in the usr/ subdirectory, e.g. fileio_tgt.
- Various documentation in the doc/ subdirectory.
Instructions for building and installing SCST are available in the INSTALL.md file.
QLogic target driver
Two QLogic target drivers are included in the SCST project.
The default driver is located in qla2x00t-32gbit directory and it supports up to 32 Gb/s FC. It is the newer one.
May anyone wish to switch back to the older driver that only supported up to
16 Gb/s adapters, it is located in qla2x00t directory. To make use of the
older driver build scst with environment variable QLA_32GBIT=no set.
Vladislav Bolkhovitin vst@vlnb.net, http://scst.sourceforge.net
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