| Message ID | 20210512202809.95363-5-danielhb413@gmail.com (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
| Series | Unisolate LMBs DRC on removal error + cleanups | expand |
| Context | Check | Description |
|---|---|---|
| snowpatch_ozlabs/apply_patch | success | Successfully applied on branch powerpc/merge (1fab3666d738e4af3a7450c44441310e4d7a7e53) |
| snowpatch_ozlabs/build-ppc64le | success | Build succeeded |
| snowpatch_ozlabs/build-ppc64be | success | Build succeeded |
| snowpatch_ozlabs/build-ppc64e | success | Build succeeded |
| snowpatch_ozlabs/build-pmac32 | success | Build succeeded |
| snowpatch_ozlabs/checkpatch | warning | total: 0 errors, 0 warnings, 1 checks, 44 lines checked |
| snowpatch_ozlabs/needsstable | success | Patch has no Fixes tags |
On Wed, May 12, 2021 at 05:28:09PM -0300, Daniel Henrique Barboza wrote: > We don't need the 'lmbs_available' variable to count the valid LMBs and > to check if we have less than 'lmbs_to_remove'. We must ensure that the > entire LMB range must be removed, so we can error out immediately if any > LMB in the range is marked as reserved. > > Add a couple of comments explaining the reasoning behind the differences > we have in this function in contrast to what it is done in its sister > function, dlpar_memory_remove_by_count(). > > Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com> Reviewed-by: David Gibson <david@gibson.dropbear.id.au> > --- > .../platforms/pseries/hotplug-memory.c | 28 +++++++++++++------ > 1 file changed, 19 insertions(+), 9 deletions(-) > > diff --git a/arch/powerpc/platforms/pseries/hotplug-memory.c b/arch/powerpc/platforms/pseries/hotplug-memory.c > index 3c7ce5361ce3..ee88c1540fba 100644 > --- a/arch/powerpc/platforms/pseries/hotplug-memory.c > +++ b/arch/powerpc/platforms/pseries/hotplug-memory.c > @@ -517,7 +517,6 @@ static int dlpar_memory_remove_by_index(u32 drc_index) > static int dlpar_memory_remove_by_ic(u32 lmbs_to_remove, u32 drc_index) > { > struct drmem_lmb *lmb, *start_lmb, *end_lmb; > - int lmbs_available = 0; > int rc; > > pr_info("Attempting to hot-remove %u LMB(s) at %x\n", > @@ -530,18 +529,29 @@ static int dlpar_memory_remove_by_ic(u32 lmbs_to_remove, u32 drc_index) > if (rc) > return -EINVAL; > > - /* Validate that there are enough LMBs to satisfy the request */ > + /* > + * Validate that all LMBs in range are not reserved. Note that it > + * is ok if they are !ASSIGNED since our goal here is to remove the > + * LMB range, regardless of whether some LMBs were already removed > + * by any other reason. > + * > + * This is a contrast to what is done in remove_by_count() where we > + * check for both RESERVED and !ASSIGNED (via lmb_is_removable()), > + * because we want to remove a fixed amount of LMBs in that function. > + */ > for_each_drmem_lmb_in_range(lmb, start_lmb, end_lmb) { > - if (lmb->flags & DRCONF_MEM_RESERVED) > - break; > - > - lmbs_available++; > + if (lmb->flags & DRCONF_MEM_RESERVED) { > + pr_err("Memory at %llx (drc index %x) is reserved\n", > + lmb->base_addr, lmb->drc_index); > + return -EINVAL; > + } > } > > - if (lmbs_available < lmbs_to_remove) > - return -EINVAL; > - > for_each_drmem_lmb_in_range(lmb, start_lmb, end_lmb) { > + /* > + * dlpar_remove_lmb() will error out if the LMB is already > + * !ASSIGNED, but this case is a no-op for us. > + */ > if (!(lmb->flags & DRCONF_MEM_ASSIGNED)) > continue; >
diff --git a/arch/powerpc/platforms/pseries/hotplug-memory.c b/arch/powerpc/platforms/pseries/hotplug-memory.c index 3c7ce5361ce3..ee88c1540fba 100644 --- a/arch/powerpc/platforms/pseries/hotplug-memory.c +++ b/arch/powerpc/platforms/pseries/hotplug-memory.c @@ -517,7 +517,6 @@ static int dlpar_memory_remove_by_index(u32 drc_index) static int dlpar_memory_remove_by_ic(u32 lmbs_to_remove, u32 drc_index) { struct drmem_lmb *lmb, *start_lmb, *end_lmb; - int lmbs_available = 0; int rc; pr_info("Attempting to hot-remove %u LMB(s) at %x\n", @@ -530,18 +529,29 @@ static int dlpar_memory_remove_by_ic(u32 lmbs_to_remove, u32 drc_index) if (rc) return -EINVAL; - /* Validate that there are enough LMBs to satisfy the request */ + /* + * Validate that all LMBs in range are not reserved. Note that it + * is ok if they are !ASSIGNED since our goal here is to remove the + * LMB range, regardless of whether some LMBs were already removed + * by any other reason. + * + * This is a contrast to what is done in remove_by_count() where we + * check for both RESERVED and !ASSIGNED (via lmb_is_removable()), + * because we want to remove a fixed amount of LMBs in that function. + */ for_each_drmem_lmb_in_range(lmb, start_lmb, end_lmb) { - if (lmb->flags & DRCONF_MEM_RESERVED) - break; - - lmbs_available++; + if (lmb->flags & DRCONF_MEM_RESERVED) { + pr_err("Memory at %llx (drc index %x) is reserved\n", + lmb->base_addr, lmb->drc_index); + return -EINVAL; + } } - if (lmbs_available < lmbs_to_remove) - return -EINVAL; - for_each_drmem_lmb_in_range(lmb, start_lmb, end_lmb) { + /* + * dlpar_remove_lmb() will error out if the LMB is already + * !ASSIGNED, but this case is a no-op for us. + */ if (!(lmb->flags & DRCONF_MEM_ASSIGNED)) continue;
We don't need the 'lmbs_available' variable to count the valid LMBs and to check if we have less than 'lmbs_to_remove'. We must ensure that the entire LMB range must be removed, so we can error out immediately if any LMB in the range is marked as reserved. Add a couple of comments explaining the reasoning behind the differences we have in this function in contrast to what it is done in its sister function, dlpar_memory_remove_by_count(). Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com> --- .../platforms/pseries/hotplug-memory.c | 28 +++++++++++++------ 1 file changed, 19 insertions(+), 9 deletions(-)