On 11/13/2012 01:39 AM, Kevin O'Connor wrote:
On Mon, Nov 12, 2012 at 03:45:19PM +0100, Hannes Reinecke wrote:
This patch adds support for LSI MegaRAID SAS controllers.
Currently only 8708EM2 is supported.
Thanks. Some comments below.
[...]
+ SET_LOWFLAT(frame->cmd, MFI_CMD_LD_SCSI_IO);
[...]
+ mlun->frame = memalign_high(256, sizeof(struct megasas_cmd_frame));
Something's not right here. If the memory is allocated in high ram,
then it isn't accessible via GET/SET_LOW. Only memalign_low memory is
available with the GET/SET_LOW macros.
I'm not at all surprised. I've still only the haziest of ideas of
how to use memalign_XX and GET/SET macros.
I actually took the ahci code as a reference on how to use those
macros, and they are using GET/SET_LOW and memalign_tmp().
So yeah, I'll be converting it to memalign_tmp().
[...]
+ struct megasas_cmd_frame *frame = memalign_high(256, sizeof(*frame));
+ int i;
+
+ memset(&ld_list, 0, sizeof(ld_list));
+ memset(frame, 0, sizeof(*frame));
+
+ frame->cmd = MFI_CMD_DCMD;
+ frame->cmd_status = 0xFF;
+ frame->sge_count = 1;
+ frame->flags = 0x0011;
+ frame->data_xfer_len = sizeof(ld_list);
+ frame->dcmd.opcode = 0x03010000;
+ frame->dcmd.sgl_addr = (u32)MAKE_FLATPTR(GET_SEG(SS), &ld_list);
+ frame->dcmd.sgl_len = sizeof(ld_list);
+ frame->context = (u32)frame;
+
+ if (megasas_fire_cmd(iobase, frame) != 0)
+ return;
Missing free(frame).
Yep.
+ dprintf(1, "%d LD found\n", ld_list.count);
+ for (i = 0; i < ld_list.count; i++) {
+ dprintf(1, "LD %d:%d state 0x%x\n",
+ ld_list.lds[i].target, ld_list.lds[i].lun,
+ ld_list.lds[i].state);
+ if (ld_list.lds[i].state != 0) {
+ megasas_add_lun(pci, iobase,
+ ld_list.lds[i].target, ld_list.lds[i].lun);
+ }
+ }
+ free(frame);
+}
Although valid, it's not a good idea to use memalign_high for
temporary space. One should use memalign_tmp for that purpose.
The thing here is that megasas_fire_cmd() is a generic function, so
it needs to work in both 16 and 32-bit environs. So the frame
pointer passed to this function needs to reference the same segment.
And this is where things get confused.
I've converted the driver to use memalign_tmp() for allocating space
for the frame. Which works.
But then you claim that GET/SET_LOW won't work for space located
high memory. However, when using memalign_tmp() it's impossible to
tell where the space is located at:
static inline void *memalign_tmp(u32 align, u32 size) {
void *ret = memalign_tmphigh(align, size);
if (ret)
return ret;
return memalign_tmplow(align, size);
}
So which macro do have to use to access this memory?
And why does GET/SET_LOW work?
Cheers,
Hannes
--
Dr. Hannes Reinecke zSeries & Storage
[email protected] +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: J. Hawn, J. Guild, F. Imendörffer, HRB 16746 (AG Nürnberg)
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