ahci: Finally fixed TRIM support.

* The maximum number of allowed ranges is now taken into account.
* Still untested on my end, however, I tested the array copying code with
  a number of test data.

src/add-ons/kernel/busses/scsi/ahci/ahci_port.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright 2008-2013 Haiku, Inc. All rights reserved.
+ * Copyright 2008-2014 Haiku, Inc. All rights reserved.
  * Copyright 2007-2009, Marcus Overhagen. All rights reserved.
  * Distributed under the terms of the MIT License.
  */
@@ -654,7 +654,6 @@ AHCIPort::ScsiInquiry(scsi_ccb* request)
 	TRACE("model number: %s\n", modelNumber);
 	TRACE("serial number: %s\n", serialNumber);
 	TRACE("firmware rev.: %s\n", firmwareRev);
-	TRACE("trim support: %s\n", fTrimSupported ? "yes" : "no");
 
 	// There's not enough space to fit all of the data in. ATA has 40 bytes for
 	// the model number, 20 for the serial number and another 8 for the
@@ -813,15 +812,37 @@ AHCIPort::ScsiReadWrite(scsi_ccb* request, uint64 lba, size_t sectorCount,
 void
 AHCIPort::ScsiUnmap(scsi_ccb* request, scsi_unmap_parameter_list* unmapBlocks)
 {
-	// Determine how many ranges we'll need
+	// Determine how many blocks are supposed to be trimmed in total
-	// We assume that the SCSI unmap ranges cannot be merged together
 	uint32 scsiRangeCount = B_BENDIAN_TO_HOST_INT16(
 		unmapBlocks->block_data_length) / sizeof(scsi_unmap_block_descriptor);
+
+	uint32 scsiIndex = 0;
+	uint32 scsiLastBlocks = 0;
+	uint32 maxLBARangeCount = fMaxTrimRangeBlocks * 512 / 8;
+		// 512 bytes per range block, 8 bytes per range
+
+	// Split the SCSI ranges into ATA ranges as large as allowed.
+	// We assume that the SCSI unmap ranges cannot be merged together
+
+	while (scsiIndex < scsiRangeCount) {
+		// Determine how many LBA ranges we need for the next chunk
 		uint32 lbaRangeCount = 0;
-	for (uint32 i = 0; i < scsiRangeCount; i++) {
+		for (uint32 i = scsiIndex; i < scsiRangeCount; i++) {
-		lbaRangeCount += ((uint32)B_BENDIAN_TO_HOST_INT32(
+			uint32 scsiBlocks = B_BENDIAN_TO_HOST_INT32(
-			unmapBlocks->blocks[i].block_count) + 65534) / 65535;
+				unmapBlocks->blocks[i].block_count);
+			if (scsiBlocks == 0)
+				break;
+			if (i == scsiIndex)
+				scsiBlocks -= scsiLastBlocks;
+
+			lbaRangeCount += (scsiBlocks + 65534) / 65535;
+			if (lbaRangeCount >= maxLBARangeCount) {
+				lbaRangeCount = maxLBARangeCount;
+				break;
 			}
+		}
+		if (lbaRangeCount == 0)
+			break;
 
 		uint32 lbaRangesSize = lbaRangeCount * sizeof(uint64);
 		uint64* lbaRanges = (uint64*)malloc(lbaRangesSize);
@@ -835,17 +856,33 @@ AHCIPort::ScsiUnmap(scsi_ccb* request, scsi_unmap_parameter_list* unmapBlocks)
 
 		MemoryDeleter deleter(lbaRanges);
 
-	for (uint32 i = 0, scsiIndex = 0; scsiIndex < scsiRangeCount; scsiIndex++) {
+		for (uint32 lbaIndex = 0;
-		uint64 lba = (uint64)B_BENDIAN_TO_HOST_INT64(
+				scsiIndex < scsiRangeCount && lbaIndex < lbaRangeCount;) {
-			unmapBlocks->blocks[scsiIndex].lba);
+			uint64 scsiOffset = B_BENDIAN_TO_HOST_INT64(
-		uint64 blocksLeft = (uint32)B_BENDIAN_TO_HOST_INT32(
+				unmapBlocks->blocks[scsiIndex].lba) + scsiLastBlocks;
-			unmapBlocks->blocks[scsiIndex].block_count);
+			uint32 scsiBlocksLeft = B_BENDIAN_TO_HOST_INT32(
-		while (blocksLeft > 0) {
+				unmapBlocks->blocks[scsiIndex].block_count) - scsiLastBlocks;
-			uint16 blocks = blocksLeft > 65535 ? 65535 : (uint16)blocksLeft;
+
-			lbaRanges[i++] = B_HOST_TO_LENDIAN_INT64(
+			if (scsiBlocksLeft == 0) {
-				((uint64)blocks << 48) | lba);
+				// Ignore the rest of the ranges (they are empty)
-			lba += blocks;
+				scsiIndex = scsiRangeCount;
-			blocksLeft -= blocks;
+				break;
+			}
+
+			while (scsiBlocksLeft > 0 && lbaIndex < lbaRangeCount) {
+				uint16 blocks = scsiBlocksLeft > 65535
+					? 65535 : (uint16)scsiBlocksLeft;
+				lbaRanges[lbaIndex++] = B_HOST_TO_LENDIAN_INT64(
+					((uint64)blocks << 48) | scsiOffset);
+
+				scsiOffset += blocks;
+				scsiLastBlocks += blocks;
+				scsiBlocksLeft -= blocks;
+			}
+
+			if (scsiBlocksLeft == 0) {
+				scsiLastBlocks = 0;
+				scsiIndex++;
 			}
 		}
 
@@ -863,6 +900,7 @@ AHCIPort::ScsiUnmap(scsi_ccb* request, scsi_unmap_parameter_list* unmapBlocks)
 			request->subsys_status = SCSI_REQ_CMP_ERR;
 		} else
 			request->subsys_status = SCSI_REQ_CMP;
+	}
 
 	request->data_resid = 0;
 	request->device_status = SCSI_STATUS_GOOD;