dma: swiotlb: introduce CONFIG_SWIOTLB_DEFAULT_SIZE_MB Kconfig

[jpagadal]

SWIOTLB default pool size is currently fixed at 64 MB via IO_TLB_DEFAULT_SIZE, with runtime override only possible through "swiotlb=" kernel parameter.

Introduce CONFIG_SWIOTLB_DEFAULT_SIZE_MB to allow setting the default SWIOTLB size at compile time. This integer option (range: 1–64 MB) depends on CONFIG_SWIOTLB and defaults to 64 MB, preserving existing behavior.

Update IO_TLB_DEFAULT_SIZE to derive from this Kconfig option.

Set CONFIG_SWIOTLB_DEFAULT_SIZE_MB to 2 MB to reduce default SWIOTLB memory footprint.

Default behavior remains unchanged unless configured. Runtime "swiotlb=" override remains supported.

CRs-Fixed: 4490764

[qlijarvis]

PR #707 — validate-patch

PR: #707

Verdict	Issues	Detailed Report
✅	0	Full report

Final Summary

1. Lore link present: No — QCLINUX: prefix; no lore link expected or required
2. Lore link matches PR commits: N/A — no lore link to compare against
3. Upstream patch status: N/A — vendor-only change, not posted upstream
4. PR present in qcom-next: Not checked — QCLINUX: vendor-only commit

Verdict: ✅ — click to expand

🔍 Patch Validation

PR: #707 - QCLINUX: dma: swiotlb: introduce CONFIG_SWIOTLB_DEFAULT_SIZE_MB Kconfig
Upstream commit: N/A (vendor-only QCLINUX: commit)
Verdict: ✅ PASS

Commit Message

Check	Status	Note
Subject matches upstream	N/A	QCLINUX: vendor-only commit
Body preserves rationale	✅	Clear problem statement and solution description
Fixes tag present/correct	N/A	Not a fix; new feature for vendor tree
Authorship preserved	✅	Jagadeesh Pagadala jpagadal@qti.qualcomm.com
Backport note (if applicable)	N/A	Original vendor contribution

Diff

File	Status	Notes
arch/arm64/configs/qcom.config	✅	Sets CONFIG_SWIOTLB_DEFAULT_SIZE_MB=2 for Qualcomm platforms
include/linux/swiotlb.h	✅	Proper preprocessor guards; backward compatible fallback
kernel/dma/Kconfig	✅	Well-documented Kconfig with range validation and help text

Verdict

Merge as-is. This is a well-structured vendor-only commit that introduces compile-time configurability for SWIOTLB default size, with proper Kconfig integration, backward compatibility, and clear documentation.

Final Summary

1. Lore link present: No — QCLINUX: prefix; no lore link expected or required
2. Lore link matches PR commits: N/A — no lore link to compare against
3. Upstream patch status: N/A — vendor-only change, not posted upstream
4. PR present in qcom-next: Not checked — QCLINUX: vendor-only commit

[qlijarvis]

PR #707 — checker-log-analyzer

PR: #707
Checker run: https://github.com/qualcomm-linux/kernel-config/actions/runs/27473666573

Checker	Result	Summary
Checker	Result	Summary
checkpatch	✅	No style issues detected
dt-binding-check	⏭️	Skipped - no DT binding changes
dtb-check	⏭️	Skipped - no devicetree changes
sparse-check	✅	Build completed successfully with sparse checks
check-uapi-headers	✅	No UAPI header changes
check-patch-compliance	❌	FAILED - Invalid commit subject prefix
tag-check	N/A	Not applicable for this branch
qcom-next-check	N/A	Not applicable - not a FROMLIST/UPSTREAM commit

Detailed report: Full report

Checker analysis — click to expand

🤖 CI Checker Analysis (checker-log-analyzer)

PR: #707 - QCLINUX: dma: swiotlb: introduce CONFIG_SWIOTLB_DEFAULT_SIZE_MB Kconfig
Source: https://github.com/qualcomm-linux/kernel-config/actions/runs/27473666573

Checker	Result	Summary
checkpatch	✅	No style issues detected
dt-binding-check	⏭️	Skipped - no DT binding changes
dtb-check	⏭️	Skipped - no devicetree changes
sparse-check	✅	Build completed successfully with sparse checks
check-uapi-headers	✅	No UAPI header changes
check-patch-compliance	❌	FAILED - Invalid commit subject prefix
tag-check	N/A	Not applicable for this branch
qcom-next-check	N/A	Not applicable - not a FROMLIST/UPSTREAM commit

❌ check-patch-compliance

Root cause: Commit subject uses QCLINUX: prefix which is not a recognized/required prefix for Qualcomm Linux kernel commits.

Failure details:

2026-06-13T17:36:00.1352301Z Checking commit: QCLINUX: dma: swiotlb: introduce CONFIG_SWIOTLB_DEFAULT_SIZE_MB Kconfig
2026-06-13T17:36:00.1367503Z Commit summary does not start with a required prefix
2026-06-13T17:36:00.1384407Z ##[error]Process completed with exit code 1.

Fix: Remove the QCLINUX: prefix from the commit subject. The commit should start with the subsystem prefix directly. Change:

QCLINUX: dma: swiotlb: introduce CONFIG_SWIOTLB_DEFAULT_SIZE_MB Kconfig

To:

dma: swiotlb: introduce CONFIG_SWIOTLB_DEFAULT_SIZE_MB Kconfig

Or, if this patch is intended to be submitted upstream or is from an upstream mailing list, use the appropriate prefix:

• UPSTREAM: if already merged in mainline
• FROMLIST: if posted to mailing lists but not yet merged
• BACKPORT: if backporting from another kernel version

Reproduce locally:

# Clone the kernel-checkers repo
git clone https://github.com/qualcomm-linux/kernel-checkers.git

# Run the check-patch-compliance checker
cd kernel-checkers
bash check-patch-compliance.sh --kernel-src /path/to/kernel \
  --base 9740e45b352ca1e5d7f40f5754b977d3533dc8b4 \
  --head 09f7a20166f58b5524057c9a9c9ec31a9e800575

Verdict

1 blocker to fix: The commit subject must be updated to remove the QCLINUX: prefix. Use standard kernel subsystem prefix (dma: swiotlb:) or appropriate upstream tracking prefix (UPSTREAM:/FROMLIST:/BACKPORT:) if applicable. Once fixed, amend the commit and force-push to re-trigger CI.